Page 1 CHEVROLET HEAVY DUTY TRUCK SHOP MANUAL...
Page 2 (Serv ice) and for disassembly and assembly of major compo ENGINE COOLING SYSTEM nents (Overhaul) for Chevrolet Series 70 and 80 Heavy Duty Trucks. ENGINE FUEL SYSTEM CHASSIS SERVICE SECTION...
Page 4 Division reserves the right to make changes in design or add improvements at any time without incurring any obligation to install same on vehicles previously purchased. TRUCK MODEL DESIGNATION i i i CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 5 6041 Aux., 7041 Aux., 14"-2 325V 13"-2 F 110 17121 18121, 17221, 541GL 541GD, 387V, TM-80 401M 478M 13" F090 14" 18221, 19201 5652, 5752C 14"-2 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 6 Service data, fits, and tolerances are listed at end of each section or sub-section under the head in the back of this manual. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 7 SURE SPECIFY APPLICABLE OPTION NUMBERS. OPTION OPTION D E SC R IPTIO N DE SC R IPTIO N Figure 4— Service Part Identification Plate CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 8: Table Of Contents
"S-27” High Temperature Grease (Special) the right lubricants when advised of the correct "S-28" High Temperature Grease (Special) specifications or descriptions. The lubricant man CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 9 LUBRICATION 0-2 Figure 1 — Lubrication Chart— Conventional Cab Models CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 10 6,000 miles or 60 days, whichever speeds. occurs first. (1) Some Models. * Or once a year, whichever occurs first. (2) Air Brake only. (3) Hydraulic Brakes only. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 11 LUBRICATION 0-4 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U A L...
Page 12 6,000 miles or 60 days, whichever speeds. occurs first. (1) Some Models. * Or once a year, whichever occurs first. (2) Air Brake only. (3) Air-Hydraulic Brakes only. CHEVROLET SERIES 70 80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 13 ★ Or once year, whichever occurs first. (1) Some Models. Figure 3 — Lubrication Chart— Tandem Bevel (SLHD, SQHD, 30DSC, and 34DSC) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 14 (1) Some Models. (2) Gas Engine Only. Replace lubricator at 24,000 mile intervals. 2,000 miles on Diesel Engines. Figure 4 — Engine Lubrication Chart CHEVROLET SERIES 70-80 H EA V Y DUTY TRUCK SH O P M A N U A L...
Page 15: Symbol Explanation " E " Engine Oil
Supplement 1 oils therefore b e c o m i n g quality "Heavy Duty" lubricating oils be used, it is unavailable. imperative that: CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 16 Daily, or oftener if necessary, check oil level. every 2 months, whichever occurs first (N O T E 1 Make the check preferably after a day's run and following). CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 17 » day. Figure 5— Gasoline Engine Oil Viscosity Chart Figure 6 — Diesel Engine Oil Viscosity Chart CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 18 G A SO LIN E EN G IN E DIESEL EN G IN E -2361 Figure 8— Engine Oil Filters Cleaner TypeI Figure 9— Air (Dry CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 19 2. Wash element thoroughly in cleaning sol vent to remove all accumulated dirt, then dry thor oughly. 3. Reinstall dry, do not oil element. Figure 10— Air Cleaner (Welted Element Type) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 20 Apply oil sparingly. ' ■ f l f S l F Figure 12— Crankcase Breather (Gasoline) Figure 13— Crankcase Ventilation System IV 6 -S3 Engine} CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 21 " M P " on charts, must satisfactorily speed conditions. It must provide necessary and lubricate heavy duty truck hypoid or bevel axles, suitable load-carrying characteristics to prevent CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 22: Rear Axle
Allison Automatic Transmission Every 6,000 miles the fluid level should be checked and fluid added as described below when Figure 14— Drain and Level Plugs— Typical Transmission CHEVROLET SERIES 70*80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 23: Transm Ission
2. When drainage is complete, remove acorn T-2451 nut, washer, cover, gasket, retainer, and filter element. Figure 15— Universal and Slip Joint Lubrication CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M AN U AL...
Page 24: Chassis Lubricant - Symbol " C
Tighten cables securely, then D ISTR IBU TO R B R E A K E R C A M recommended intervals, apply a small apply petroleum jelly. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 25: Waterproof Grease - Symbol "S
Window Regulators system must be bled out, otherwise noisy and un Hood Hinges satisfactory operation will result. Tilt Cab Guide Pin CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 26: High Temperature Grease (Special)
Suppliers should assure these characteristics, and your Chevrolet engine. be responsible for the quality and satisfactory per formance of their products. CHEVROLET SERIES 70 8 0 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 28 An application of D C 4 X silicone or equivalent panel pad. Water which shows up at a certain place CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 29 F R A M E (SEC. 2). black or other automotive lacquer. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 30 If new insert is being used, cut off insert b. Irregularities in body opening. allowing sufficient overlap for a tight joint; then c. Irregularities in rubber channel. butt into groove. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 31 Remove hex crown nut and washer which at tach wiper arm to knurled driver and pivot shaft. Relocate arm on driver to desired position. figure 3— Wiper Motor installed (Cow. Cob Models) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U AL...
Page 32 Shaft Assembly DRIVE LINKAGE DISASSEMBLED DRIVE UNIT A N D M O T O R ASSEMBLED Figure 5— Wiper Motor and Drive Components (Tilt Cab Models) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 33 Figure 7— Wiper Blade Angle Adjustment position. Reposition arms if necessary. (Tilt Cab Models) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 34 Arm ature—^ HIG H SPEED CIRCUITS Figure 10— Motor Crank Arm Lever Figure 9 -H ig h -L o w Speed Circuits Location in “Park" Position CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 35 Housing is attached with two Figure 12 —Motor Drive Unit Disassembled For screws, nuts, and washers. Access To Parking Switch Contacts CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 36 "L o w " speed only, the Check for loose wiper ground connection and or loose dash switch mounting. terminal No. 3 and dash switch CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 37 The pumping mechanism is powered by a four- lobe cam which is pressed on wiper motor output shaft. This cam Figure 13— Washer Pump Attaching Screws CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M ANUAL...
Page 38 MOUNTINGS 1-11 C A B A N D B O D Y rotates whenever the wiper motor is running. Pro a. Reservoir contains water solution. gramming is accomplished electrically and mech b. Hoses are not damaged and hose connec anically through use of a pump solenoid circuit tions are tight, and ratchet wheel arrangement.
Page 39 5 Ratchet Pawl 16 Ratchet Pawl Spring 11 Dog Retaining Screw 6 C am Follower Lower Pin Figure 7— W asher Pump M echanism CHEVROLET SERIES 70-80 H E AV Y DUTY TRUCK SH O P M A N U A L...
Page 40 Separate valve assembly from valve body and pipe assembly. Hose connections piston housing. on pipe assembly should be pointed in same direc tion as original position. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN U AL...
Page 41 (30- 40 Torque) M O U N T IN G BOLT I — Cafe Figure- W elded Comtruction Figure 2— C ab front M ounting CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 42 4 -F u ll-W id th Seat Back Adjustment CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 43 2. With aid of an assistant to support weight purpose of storing heavy tools in door compart of door, remove three cap screws which attach ment. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 44 Perform clearance adjustment at rear of door as directed later under "Door Striker." See "Door Rear Edge "In" or "Out" Adjustment." Figure 6— Door Clearances CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 45 STRIKER BOLT M ARK CENTER OF LOCK ' V IN PAINT OR C R EA SE Figure ? 0 —■ Striker Bolt Alignment Points CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 46 After obtaining proper fore and aft adjustment, tighten bolt snug only at this time and then proceed 12 —Door with the "Striker Bolt Height Adjustment.” Figure Check Installed CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 47 CAB A N D BO DY M O U N T IN G S 1-20 Striker Bolt Height Adjustment This adjustment is important to assure that the right proportion of door's weight will rest on striker bolt when door is closed. If bolt is posi tioned too high on pillar, rapid wear will occur to the lock cam;...
Page 48 17. Remove shaft spring and button assem Figure 17— Disengaging Handle Spring Retainer bly with O-ring seal from handle. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 49 N O T E : Figure 20 illustrates the components the retainer flange will not be vertical in door slot. of the lock and remote control mechanism. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 50 "Door Lock Cylinder Replacement." special tools. 3. Cut new piece of glass channel rubber filler, 6. At rear edge of door, remove three special CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 51 CAB A N D BO DY M O U N T IN G S 1-24 CLIP EN G A G ED CLIP D ISEN G A G ED T -2 5 49 Figure 2 7 — Disengaging Door Pull Rod Fasteners two inches longer than required.
Page 52 Window glass rubber filler is supplied in ITS, 3.. Install two .screws attaching lower channel three thicknesses - 0.037", 0.047", and 0.057” - CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 53 "Door Vent Window Assembly Replacement." 6. Check operation of vent assembly and win Gloss dow raising and lowering action for possible binding. Figure 28— Installing W indow Channel Run CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U AL...
Page 54 Place cab mounting components in position 10. Disconnect parking brake if of the mechan on chassis frame brackets. Refer to figures 2 ical type. and 3 for location of mounting components. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 55 " M E D I U M " and " L O W " speed switch positions. Figure 3 0 — Standard Duty Air-Flow Heater CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 56 CAB AND BODY MOUNTINGS 1-29 “AIR” T-2428 HEATER CONTROLS Figure 31— Heavy Duty Air-Flow Heater CHEVROLET SERIES 70 -S0 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 57 The control on dash marked "A IR " regulates assembled for inspection or replacement of the the flow of outside air which passes through the blower, motor, core, etc. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U AL...
Page 58 A single vent intake at front center of cab after disconnecting the attaching air hoses and the cowl (fig. 33) permits outside air to enter cab CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 59 Refer to "G E N E R A L M A I N T E N A N C E " at beginning of this section for information on straightening, dinging, refinishing and painting of cab which will apply. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U A L...
Page 60 No sealing com pound or cement is used. Rear window glass and Figure I — Tilt Cab Interior (Typical! CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 61 H required, make adjustment as directed later under "Torsion Bar Tension Adjustment." figure 2— Re/easing Cab Hold-Down Mechanism CHEVROLET SERIES 70 80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 62 C A B REAR M O U N T IN G CA B FRONT M O U N T IN G Figure 4— Cab Mountings CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 63 CAB AN D BODY MOUNTINGS 1-36 includes an addition; N O T E : Whenever torsion bar is in n !> i ; Tightness of cal operative, cab must be supported safely. ed by shortening or lengthening catch elpi'tbe f 'm i Attaching bolts at front pivot mountings should til:!.
Page 64 R E P O SIT IO N D O O R " F O R E " O R " A F T ” (Fig. 7) Only the upper portion of door can be adjusted Figure 8 — Door Striker Bolt and Washers CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN U AL...
Page 65 This adjustment is important to assure that the right proportion of door's weight will rest on Figure 9— Sight Striker Bolt Alignment C h e ck in g Figure 10— Striker Bolt Alignment CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M AN U AL...
Page 66 1. Mark a horizontal line on cab pillar at top of striker bolt base washer or spacer. 2. Loosen striker bolt slightly, then tap against bolt base washer, to move bolt "in" or "out" as CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M ANUAL...
Page 67 It may be necessary to drive retainer into final engagement with a light hammer. 3. Insert key and check operation of lock. If Figure 15— Disengaging Door Inside Handle CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U AL...
Page 68 N O T E : Figure 16 illustrates the position of at pull-rod. Separate rod and remove control from the lock and remote control mechanism components. door. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 69 IN S T A L L A T IO N (Figs. 16 and 17) Install lock mechanism with rods and remote Figure ? 8 — Rem oving Regulator Arm From Track CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M A N U AL...
Page 70 2. Thoroughly clean inside of glass channel by removing all rust and old glazing rubber filler. Figure 20— Removing Door W indow Class CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 71 N O T E : Door division channel is not part of the clamp. door vent window assembly. However, instructions CHEVROLET SERIfrS 70-80 HEAVY DUTY TRUCK SHOP M ANUAL...
Page 72 2. At bottom of vent glass (fig. 23), place hand (Refer to Figs. 23, 24, and 25) to catch vent friction components, then remove 1. Thoroughly clean inside of glass channels CHEVROLET SERIES 70-30 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 73 From the plenum chamber, outside air The outlet located ahead of driver is opened CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 74 3. Open heater temperature control on dash to full open position, and drain radiator. Disconnect heater hoses at cab connections. Figure 2 8 — Lifting Sling Attached to Cab CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 75 Figure 3 0 — Hold-Down Catch at Rear Chassis Figure 31-—Cab and Disconnect Points (Typical) Cab Resting on Block CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 76 6. Slide torsion bar from cab right frame bracket, then slide bar in opposite direction from cab left support. figure 32— Torsion Bar Tension Adjustment Lever Installed CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M AN U A L...
Page 77 N O T E : This unloaded angle position will vary IM P O R T A N T : Final check tightness of anchor slightly on different vehicles. lever bolt nut. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 78 8 Lock Nut 2 Longitudinal Sill 5 Clip Plate 9 Nut 3 Spacer Block Metal Channel 10 Cross Sill 7 Mounting Bolt Figure 1 — Typical Body Mountings CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U AL...
Page 79 (studs) can also be successfully mounting of sill channels. employed. If design of body does not permit use CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 80 Shoulder of bolts should be driven with plates or washers. into holes to prevent bolts turning. If U-bolts are CHEVROLET SERIES 70-00 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 81 1 shows typical arrangement of system units and 2. A fin and tube-type condenser coil mounted controls. to front of engine radiator. 1 — General Arrangement of Air Conditioning Units Figure CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 82 Valve is stuck open and too much refrig belt slippage and listen erant is entering evaporator. Replace for unusual noises. expansion valve. See Note " E . ” CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U AL...
Page 83 2. A refrigerant expansion valve, also located unit mounted at left side of dash unit. Motor is in above mentioned housing. Valve is mounted just controlled by dash switches. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 84 The small outlet door at base of dis tributor duct can be opened if desired by pulling downward on door tab. Figure 2 — Air Conditioning Control Switch CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A 1...
Page 85 C O N D IT IO N IN G COMPRESSOR - - / 6 - 0 .G M .- 3 9 -------------- Figure 4 — Air Conditioning Wiring Diagram CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 86 For example, the steam caused by boiling water on a stove will condense into water on the underside of the cover. Figure 5-Pressure-Temperature Chart CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 87 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 88 Refrigerant control units and piping is illus refrigerant at the evaporator outlet. 7. The low pressure refrigerant gas passes trated in figures 1 and 6. A complete cycle of the CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 89 (fig. 7). CHEVROLET SERIES 70-60 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 90 Figure 8— Suction Throttling Valve CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 91 Maximum operating pressure may be obtained by a common output. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 92 Liquid refrigerant from the condenser enters the pulley shaft face (which rotates freely about the receiver to flow into the upper portion of the the compressor shaft). receiver which contains desiccant confined in a CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M ANU AL...
Page 93 4. Compressors are shipped with 10 - 11 oz. with "General Information" on refrigeration serv of Frigidaire-525 Viscosity Oil and charged with ice. a mixture of Refrigerant-12 and dry nitrogen to CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 94 5. Do not connect the receiver-dehydrator as charge of refrigerant is in the system and that it sembly until all other sealed sub-assemblies have is functioning properly. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 95 After at condenser in auxiliary fan air stream. least five minutes of engine operation,, observe for 5. Place a second calibrated thermometer in CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 96 TO VA CU UM PUMP, REFRIGERANT, OR REFRIGERANT OIL GAUGE SET GAUGE HOSE CONNECTIONS AT COMPRESSOR Figure J 3 — Hook-Up of Gauges and Evacuating Pump CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 97 J-5428-02 (fig. 13). rapidly. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 98 Frig ating, then stop pump. idaire-150 viscosity oil or equivalent. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 99 N O T E : If air inlet temperature is below 70°F ., approximately 100 pounds). when this check is made, bubbles may appear even CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 100 N O T E : If line at center gauge fitting has not system for leaks as explained later under "Check been purged of air, loosen line at center fitting on ing For Leaks.” CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 101 For each 1000 feet above sea level where high pressure gauge hose and discharge gauge this operation is being performed, the specifica fitting. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 102 CAB A N D BO DY M O U N T IN G S 1-75 2. Start engine, turn air conditioning temper from the top of the retainer, slip the valve ature control to full cold position, blower control onto the can and turn the valve into the re for high speed, and also move "A IR "...
Page 103 C A U T IO N : Do not use lighted de tector in any place where combustible or explosive gases, dusts or vapors may be present. Figure 15— Checking for Refrigerant Leak CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 104 2. If amount drained in step 1 above is more than 1-1/2 fluid ozs., subtract this amount drained unit. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 105 See lower portion of figure 16. cloth and, if necessary, clean front of compressor CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 106 5. Evacuate complete system. be reduced. See "Checking Compressor Oil Level 6. Charge complete system. and Adding Oil" previously. 7. Make performance test. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 107 8. Make a performance test. turning the drum upside down and opening the drum CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 108 ..... 15 to 3 0 m in CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 109 Tighten all connections in accordance with recommended torques. ensure maximum moisture protection, do not connect the receiver- dehydrator until all other assemblies have been connected. CHEVROLET SERIES 70-80 H E AV Y DUTY TRUCK SH O P M A N U A L...
Page 110 1 /8 " of the centerline, the portion of the frame Figure 1 — Typical Frame Alignment Points CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 111 M o x . B e n d in g M o m e n t T -2993 Figure 2 — Frame Bending Moment (Typical Tractor) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 112 However, it must where necessary. Figure 3 — Frame Bending Moment (Typical Straight Truck) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 113 Instructions.") of U-bolts for attachment of fifth wheels or bodies T -2 9 94 Figure 4— Frame Bending Moment (Typical Dum p Truck) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 114 E12016 or E11018. Following tiple sunburst cracks which will radiate from a are the descriptions of the types of welds and hole in the web section. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 115 For this reason it is extremely important that all reinforcement ends be scarfed to change section modulus as grad Figure 6— Scarfed (Tapered) Ends of Reinforcement CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 116 The inverted " J " reinforcement is attached to the 2. Reinforcements, with the exception of strap web section only with a spaced bolt pattern. This CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 117 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 118 Type of Electrode E-7016 E-11018 Alternate Electrode Fram e repairs should be undertaken only by competent mechanics, and only the recommended materials should be used. CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 120 2. Refer to W H E E L S A N D TIRES (SEC. 10). 3. Refer to Load and Inflation Table (SEC .10) 3. Improper tire inflation. 4. Avoid overloading vehicle. 4. Overloaded or improperly loaded. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 121 5. Check king pins for looseness. to scribe the tires, otherwise the front wheels will CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 122 (fig. 1). level. If alignment check is to be made with frame If readings still vary over 1 /4 °, replace steering CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 123 L. 5 3/4° R. & L. 8“ 6 1/4° 6 1/4° R. 6 1/4° 1/8” to 1/4" 1/8" to 1/4" 1/8" to 1/4” 1/8" to 1/4” CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 124 R E A M A N D BUSH D R A W K E Y H O L E S . Screw Adjustment Typical CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 125 The king pin is held in place with a tapered M E N T " (SEC. 3A). Inability to correctly align draw key, installed as shown in figure 2,. The draw CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U A L...
Page 126 4. Remove cap screws attaching upper and ance between knuckle lower yoke, thrust bearing CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 127 Install steel spacer (6) nuts and cotter pins. on top of bushing. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 128 Magna-Flux method to check axle center Magna-Flux inspection equipment is available, use for minute fractures. this method to inspect steering knuckles and king Refer to next page for Specifications. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 129 B u s h i n g - N o F i n i s h i n g R e q u ir e d ‘ " R e a m A f t e r I n s t a lla t io n CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M A N U A L...
Page 130 3. Check load capacity rating. Spring Breakage 1. Loose U-bolts. 1. Tighten to recommended torque. 2. Normal fatigue. 2. Replace spring. 3. Overloading. 3. Check load capacity rating. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 131 REAR MOUNTING— MODELS TM80 CONV. C AB R E A R S H A C K LE Figure 1 — Front Spring Front and Rear Mountings (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 132 Thoroughly clean spring bushings, Figure 4— Removing Spring Pin or Bolt With bracket or shackle bushings, and shackle or bracket Slide Hammer and Adapter CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 133 Figure 6— Installing Rubber-Type Bye Bushing CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 134 Install clamp bolts and fitting. IMPORTANT U-bolts must be retightened to initial torque listed in "Specifications" after 500 miles. Refer to next page for "Specifications." CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 135 ....................30-40 Front Spring Rear Bracket-to-Side Rail Bottom Flange ( T M - 8 0 ) ....................... 30-40 Shock Absorber Nuts ( A l l ) ..............70-80 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 136 2. Remove cotter pin securing adjusting nut of non-hardening sealing compound; then press to spindle. new oil seal in hub, until seal case seats against CHEVROLET SERIES 70-60 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 137 6. Make sure oil deflector or shield is in 8. Install tire and rim or tire and wheel as place on axle spindle; then carefully install hub semblies. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 138 Do not spin bearings while blow ing them dry. the roller bearings are damaged, the complete 2. Thoroughly clean all lubricant out of inside bearing assembly must be replaced. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 139 Remove bolts and lock nuts, or studs and firmly bottomed in tapped holes and that nuts, attaching brake drum to hub. threads are not damaged during installation. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U A L...
Page 140 H IG H and to opposite field when in L O W . Refer to Section 12. Figure 1 -T w o-Speed Axle Electric Shift Controls CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 141 (fig. 4). Figure 3— Position of Drive Screw in High and Low Range CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 142 A X L E S H A F T F L A N G E M O U N T IN G Axle shaft flanges are retained to hubs with stud nuts and dowels on all axles. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 143 3. If this fails to correct leakage, remove line cuit is satisfactory and any trouble will probably having leaking connection. Slide tube nut back on CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 144 IN T E R M IT T E N T NOISE Warped Bevel Gear ......... Replace Lack of Air Pressure ......Correct Low Vacuum ........... Correct Loose Differential Case Bolts ....Tighten CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 145 9. Reconnect air brake lines as directed in brakes for proper application. BRAKES (SEC. 5). CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 146 Remove yoke nut (fig. 7) and washer, then remove yoke using suitable puller (fig. 8). Remove bearing retaining washer. Figure 8— Propeller Shaft Yoke Puller (Typical) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 147 10. Perform additional installation operations 3. Tighten all nuts evenly and alternately until carrier is in position. Replace temporary flat directed later under heading "All Axles." CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U A L...
Page 148 5. Install split tapered dowel over each stud. Install and tighten 5 /8 " nuts to 50-60 ft.-lbs. torque Figure 11 — Electric Shift Unit Seal Markings CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 149 Use suitable available tool to press or drive Figure 13— Inter-Axle Air Shift Chamber and Spring (Eaton) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 150 Position new gasket on differential carrier cover, also install spring over shift fork shaft Figure IJ A — Shift Unit Cover Removed (Rockwell Axle) (fig. 13). CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 151 CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 152 17. to prevent damage to drive nut contact bumper, 1. Remove six screws (28) and lock washers and is also necessary in assembly. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 153 28 Housing Cover to Housing Screw (with Washer) 4^. 9 T P - 8 5 9 8 -1 Figure 17— Electric Shift Unit Components (Eaton! CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 154 Figure 19— Removing Shaft, Actuating Lever, and Spring shift unit disassembly as illustrated in figures 20, TP-8605-; Figure 20— Removing Drive Screw Bearing Figure 22— Removing Motor CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 155 With the Figure 24— Disassembling Torsion Spring from Lever CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 156 25 Shift Housing Cover and Detent Spring 26 Lubricant Plug 27 Housing Cover to Housing Screw (with Washer) 28 Housing to Carrier Seal Figure 25— Shift Unit Components (Rockwell) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 157 10. Remove oil plug (27). With unit standing with motor up, lubricate in accordance with in- Figure 26— Removing Torsion Spring (Rockwell) Figure 28— Assembling Torsion Spring and Levers (Eaton) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 158 Nut, plain washer, small dia T -3 3 2 9 phragm plate, diaphragm, large diaphragm plate, plain washer, and nut. Figure 29— Inter-Axle Air Shift Chamber CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U AL...
Page 159 "Maintenance on Vehicles." CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 160 % " ............... . . 90-110 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 161 On tilt cab models, a spacer is used at bottom figure 4 and remove rebound pins. of spring pile to separate the last leaf from the Figure 1 — Pinned Type Hear Suspension (Typical) CHEVROLET SERIES 70-8CI HEAVY DUTY TRUCK SH O P M A N U A L...
Page 162 M O U N T IN G BRACKET TORQUE ROD ' U-BOLT ASSEMBLY ■U-BOLT NUT SPRING ANCHOR PLATE CONVENTIONAL CAB MODELS (TYPICAL) Figure 2 — Link Type Hear Suspension (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 163 5. Compress radius leaf with a C-clamp until Figure 4 — Removing Radius Leaf Pin With Slide radius leaf eye and hanger holes are aligned. Hammer and Adapter CHEVROLET SERIES 70 80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 164 W hen used, the auxiliary spring leaves are install ed above the regular rear spring assembly and are held in place by long U-bolts. Brackets are Figure 6 — Removing Spring Eye Bushing CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 165 RT-type and adjustable rear plete tandem unit should be removed from the rod on RU-type. Figures 8 and 9 show typical CHEVROLET SERIES 70-80 HEAVY" SH O P M A N U A L D U T Y T R U C K...
Page 166 25 Stud Nut 12 Lock Nut 26 Saddle Caps 13 Lock Washer 14 Top Pad Slide COMPONENTS DISASSEMBLED Figure 8 — Tandem Rear Axle Suspension (Hendrickson-RT) (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 167 12 Cap Screws 6 Frame 20 Spacer 13 Spring Saddle Cap 7 Forward Rear Axle 14 Equalizing Beam T-2878 Figure 9 — Tandem Rear Axle Suspension (Hendrickson-RU) (Typicall CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U AL...
Page 168 6 Spring Pin Lock Bolt T-1001 Figure 11 — Tool Application for Replacing Figure 12— Section Through Spring Eye Spring Eye Bushing and Front Bracket ITypical) CHEVROLET SERIES 70 -S0 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 169 Make to parts. sure lubricant passages in pins are open. CHEVROLET SERIES 70-8CI HEAVY DUTY TRUCK SH O P M A N U A L...
Page 170 3. Install top pad to saddle bolts and nuts and Remove equalizing beams and cross tube tighten snugly. Tighten top pad set screws as described under "Equalizing Beam Removal” CHEVROLET SERIES 70-80 H EAV Y DUTY TRUCK SH O P M A N U A L...
Page 171 BU S H IN G R E P L A C E M E N T described later under “ Equalizing Beam Press old bushing out, using a suitable driver Installation.” or press to exert force on bushing outer sleeve. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 172 3. Install spring saddle caps to attach beam housing using a soft hammer. center bushing to spring saddle. Install saddle cap 2. At frame end, remove self-locking nuts CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 173 When a major overhaul is required, the com pivoting at rocker arm ends when torque rods are plete tandem unit should be removed from the disconnected. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 174 14 Rocker Arm 9 U-bolt 4 Pedestal Spacer 10 Insulator Cap 15 Spring Cap 5 Frame Figure 18— Page and Page ILWH1 Rear Suspension Installed (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 175 8 Cross Tube 17 Adapter Bolt 26 Pedestal to Cross Tube Nut 1.2374 Figure 19— Page and Page (LWH) Rear Suspension Removed (Typical) CHEVROLET SERIES ' 0 -HO H EAVY DUTY TRUCK SH O P M A N U A L...
Page 176 Slide trunnion mount assembly ment. IMPORTANT U-bolts must be retightened to initial torque listed in "Specifications" after 500 miles. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 177 100-120 Equalizing Beam End Bolt N ut..........190-210 Torque Rod to Axle Housing Stu d ....120-150 Vertical Drive Cap Bo lts............100-125 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 178 IM P O R T A N T Tighten all U-bolt nuts to torque listed in "Specifications" after miles of operation. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M A N U A L...
Page 179 "R E A R A X L E S " (SEC. 4A). A X L E S " (SEC. 4A). Figure 1— Rear Wheel Bearing Adjustment Nuts CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 180 2. If brake drum is demountable type, remove brake drum. dropping on floor. Remove outer bearing assembly. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 181 Coat oil seal bore in hub with a thin layer of non 6. Install brake drum (if removed). Install hardening sealing compound. tire and rim assembly or tire and wheel assembly. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 182 Alternately drive sleeve is not damaged in any way. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 183 N O T E : Refer to "Service Diagnosis Chart" on propeller shaft is used, slip joint is at transmis following page when servicing propeller shafts. Figure 1— Typical Propeller Shaft Combinations CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 184 ■ 3 Special Cap Screw Figure 2 — Type S 8 W B Universal joints Sh ow ing H igh and Low W in g Bearings CHEVROLET SERIES 70-B0 HEAVY ix irY TRUCK SH O P M AN U AL...
Page 185 5 are of the same construction except for shape bearings are used, it is necessary to disconnect and location of dust slingers. View B illustrates center bearing support from crossmember. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 186 Type 58WB (Figs. 2 and 3) force one bearing out of yoke. Strike opposite side of yoke to force opposite bearing out. Remove special cap screws and lock washers CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 187 . ’ i l M SUSPENSION 4D-48 9 Bearing Assembly . * Nut 5 Cushion Retainer 10 Propeller Shalt Center Bearing Support Y o ks 11 Dust Shield 3 Dust Shield 7 Grease Retainers 12 Washer i- so ii 4 Rubber Cushion Siingers Figure S —...
Page 188 C A T IO N (SEC. 0) to needle rollers in each bear N O T E : If a new propeller shaft is to be in ing to provide initial lubrication. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 189 View C, figure 6 , then rotate shaft until bubble CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M ANUAL...
Page 190 REAR SUSPENSION 4D-51 E— CHECKING FORWARD REAR AXLE PINION ANGLE Figure 6— Checking Drive Line Angles CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 191 ROCKWELL SLHD A N D SQHD EATON 34DSC TYPICAL O N ALL J A N D M MODELS T-3036 Figure 9— Typical Torque Rods Installed (Adjustable Type) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 192 N E E D L E S N E E D L E S B E A R I N G 0.78125" 1480 0.8942"-0.8947" 0.0936"-0.0938" 58 W B 1.0621"-1.0625" 0.0928"-0.0930" 0.819"-0.839" CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 193 T O - C R O S S M E M B E R B R A C K E T B O L T 25-30 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 194 At least once a year, drain and flush entire wheels and brake drums. Adjustment points are brake system and refill with new fluid. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 195 Replace all stud and adjust second shoe by repeating steps 1 rubber parts. Refill system with recommended and 2 . fluid. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 196 Make sure fluid level in pressure tank is wheel cylinders are accessible at inner sides of up to petcock above outlet and that tank is charged the backing plates. R evised 1968 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 197 Brake pedal should be pumped up and down slowly, 5. If, after bleeding, the pedal "feel" is not and should be on downstroke as valve is closed. CHEVROLET SERIES 70*60 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 198 2. Install bushings in sleeve. Insert clutch Figure 5— Brake Pedal and Master Cylinder pedal shaft through sleeve and install spring washer Installation (Conventional Models! CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 199 2. Install bolts which fasten bushing assembly is too short, excessive pedal travel will be re to cab sill. Tighten securely. quired to apply brakes. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 200 3. Pedal binding on shaft, preventing full re tach cylinder with three bolts. Tighten bolts firmly. turn of piston — free up and lubricate pedal. CHEVROLET SERIES 70 -80 H EAV Y DUTY TRUCK SH OP M A N U A L...
Page 201 Remove snap ring from groove in both cyl Master cylinder repair kits are available inder bores. which contain all the parts ordinarily required CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK S H O P M A N U A L...
Page 202 Jack up axle and remove brake shoes as taching each cylinder to backing plate, then remove directed under "Brake Shoe Removal." cylinders from backing plate. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 203 Repair kits are available which contain the -2 6 75 - t p m parts to be replaced when overhauling wheel cyl inders. Figure 8 — Wheel Cylinders CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 204 All other CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 205 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 206 2. Connect all hydraulic, vacuum, and atmos and cleaning is N O T recommended. When cleaner pheric lines and hoses to power cylinder. Revised i 9 6 8 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 207 The repairable type has a cast metal body channel on left-hand side (see fig. 13). Figure 13— Vacuum Check Valves Installed CHEVROLET SERIES 70-80 H EAV Y DUTY TRUCK SH O P M A N U A L...
Page 208 Each shoe is adjusted by means of an eccen direction of drum rotation. tric cam which contacts a pin pressed into brake CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 209 Each adjusting screw is thread ed into or out of its support by means of an adjust- tation. Brake anchor supports and backing plate CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 210 Refer to "Brake When replacing linings, make sure that shoes are D r u m s " following: clean and that linings are installed in a manner CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 211 D is p la c e m e n t ....2.46 cu . in. 3.2 cu . in. 4.7 c u . in. 3.2" CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 212 8 . Sand surface of linings. 8. Glazed linings. 9, Replace or resurface drums in R .H . and L .H . 9. Bellmouthed, barrel-shaped or scored drums. p a irs. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 213 1. Replace lining with lining recommended. 2, Poor lining contact. 2. Grind lining to proper radius, adjust. 3. Thin drum. 3. Replace drum. 4, Dragging brakes. 4, Adjust, CHEVROLET SF R E S 70-80 HEAVY DUTY TRUCK SH O P M AN U AL...
Page 214 6 . Remove any foreign material from all of the 6 . Water, mud, etc., in brakes. ■ brake parts and inside of the drums. Lubricate the shoe ledges. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 215 7. Replace defective parts. 8 . Loose wheel bearings. 8 . Tighten to proper setting. 9. Loose backing plate, drum, wheel cylinder. 9. Tighten. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK S H O P M A N U A L...
Page 216 PROBABLE CAUSE R E M E D Y 1. Replace defective parts. 1. Bent, broken obstructed tufre. Collapsed hose. 2. Stuck check valve. 2. Replace valve. CHEVROLET SE R ES 70-80 H EAVY DUTY TRUCK SH O P M ANUAL...
Page 217 CHEVROLET SERIES 70-80 H E A V Y DUTY TRUCK SH O P M A N U A L...
Page 218 Line 5 Air Intake 23 Safety Valve .2344 17 Air Tanks 6 Governor 11 Air Gauge Figure 1— Schematic Diagram of Typical Air Brake System CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 219 Figure 2 — Brake Pedal and Application Valve Installed (ConventionalI Typical) and brakes will not release. If it does not open far CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U A L...
Page 220 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 221 Slide slack on rear brakes of series 70 and 80 tilt models, adjuster off end of shaft. and for front brakes are covered here. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 222 Apply brakes and see that the brake chamber the left frame rail, under the cab in the step area. CHEVROLET S E R K 7 0 80 H W V Y DUTY 1RUCK SH OP M A N U A L...
Page 223 All air lines are interconnected in a manner similar to the single axle models. the valve cap from the air tank. Use caution when CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 224 With brakes applied, cover exhaust port CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 225 Quick release valve is used as standard equip ted under "Serviceability Tests." ment at both front and rear brakes on some models, CHEVROLET SERIE5 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 226 All valve ports, mounting holes and check valve, stop light switch, etc. These items CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 227 Service instructions for metal tubing follow: Connections should be tested at least every 5,000 Metal lines are of annealed copper tubing with miles and tightened or replaced, if necessary. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 228 The rubber gaskets should be replaced every Figure 11— Trailer Brake Connections (Conv. Model Shown) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 229 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 230 3. Start engine and build up air pressure. 2. Drain air from brake system. 4. Check for leaks and operation of brakes. 3. Disconnect air lines from valve. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 231 3. Disconnect air lines. panel which is illustrated in figure 14. 4. Remove mounting bolts and valve. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 232 4. Check for leaks. brake service line. Check valve is installed in 5. Check operation of brakes and stop lights. delivery port in brake application valve. Air line CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 233 (to direct the three major units connected by air lines. These flow of air pressure to either parking or locking CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 234 _Plunger Valve Carrier Front Brake Chambers DRY R O A D POSITION Limiting— Quick Release Valve Figure 15— Front Brake Limiting and Two-Way Control Valve Operation CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 235 The diaphragm the ramp on the collar to engage them with the push plate shaft. moves the push plate and shaft out, applying the CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 236 INLET VALVE SEAT RESERVOIR A TM O SPH ER IC AIR SUPPLY SO URCE Figure 16 — Schematic Diagram 0 0 3 B rake Actuator System CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 237 A service applica If necessary, disconnect slack adjuster from cham tion of approximately 100 psi will release the ber push rod clevis. brakes. CHEVROLET SERIES 70-80 H EA V Y DUTY TRUCK SH O P M A N U A L...
Page 238 The inver sion valve also operates automatically when air pressure drops to a predetermined pressure (40 Figure 77— DD3 Brake Actuator System Installed at Rear Axle Psi). CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 239 BRAKES 5B-46 The inversion valve employs a 1-1/ 4 " diam INVERSION VALVE eter hole mounting. The valve serves as a mani OPERATING AND LEAKAGE CHECKS fold having a total of six (6) 1/ 4 " pipe ports: three O P E R A T IN G (3) control ports, two (2) delivery ports and one (1) supply port.
Page 240 4 Camshaft Seal 15 Lock Ring 5 Camshaft Bushing 9 C am Roller 16 Anchor Pin 10 Brake Shoe -1584 Figure 19— Front Brake Assembly IWagner) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 241 A L L M O D E L S cam head; anchor pin ends should be coated with One-piece molded lining is riveted to each CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 242 Refer to " F R O N T HUBS A N D B E A R IN G S" (SEC. TPM -8228 3D) for removal of wheels, hubs, and brake drums for access to brake shoes. Figure 20 — Front Brake Assembly (Rockwell) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M AN U AL...
Page 243 Camshaft and Brake 12 Slack Adjuster 17 Roller Pin Chamber Bracket 13 Lock Ring 18 Brake Shoe Lining TPM-7630 Figure 21— Rear Brake Assembly (Wagner) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 244 S A F E T Y P R E C A U T IO N . es the lining to drum fit. When machining drums, CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M AN U AL...
Page 245 Kiures covering the removal and install- ratomatic adjuster components are given owing paragraphs: f i g u r e CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M AN U A L...
Page 246 See LU BR ICATION housing. (SEC. 0) for type of lubricant to be used. 3. Remove spring and plunger guide. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 247 4. Examine diaphragm plate rod boot for de 6, Install spring, gasket and bolt. terioration or cracks. If deterioration or other CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 248 N O T E : Mark adjusting end of brake Figure 28— Staking Air Chamber shoes to insure correct reassembly. Lockwasher CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 249 Cotter Pin Identification Ring Spanner Nut "Failsafe" Air Chamber Standard Air Chamber Lock Washer 32 Nut T-2291 Figure 29— Stopmaster Brake Components (Automatic Adjuster with “Fail-Safe") CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U A L...
Page 250 2. Slide wedge spring off wedge. 3. Remove wedge retainer washer and rollers from roller retaining cage. Figure 31— Installing Seal on Anchor Plunger CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 251 IN S T A L L A T IO N (Refer to Fig. 29) Install new seals on anchor plungers as shown in figure 31. Figure 3 3 — Plunger Seal Installing Tool Dim ensions CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M AN U A L...
Page 252 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U AL...
Page 253 O-ring seal in the pressure housing. pressure from the parking brake chamber, move If leakage occurs, replace O-ring with new part. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 254 BRAKES 5B-61 9 Washer 17 Housing to Plunger " O " Ring 1 Spanner Nut Retaining Washer 18 Air Chamber Piston Plunger 2 Spanner Nut 10 Bolt 11 Non-Pressure Housing 3 Wedge Rod Guide Assembly 12 Push Rod Boot 19 Air Chamber Cap Assembly 4 Tag Nut 13 Diaphragm Plate Rod 5 Caution Tag...
Page 255 Inspect external threads on cap for rust or cor compressed, cocks slightly. It is then necessary rosion. Figure 4 0 — Rem oving Pressure Housing with “Strap" Wrench CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 256 When 65 psi or more of air pressure is applied the cap allows system air to fill the vacuum behind against the piston, the power spring will be held in CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 257 20 Wedge Guide 10 Breather Assembly 21 Wedge T- 5 9 2 2 Figure 42— Brake Assembly with Super “Fail-Safe” Figure 43— Super “Fail-Safe" Assembly CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 258 5. Install outer flat washer and O-ring on re hot soapy water and wipe clean. lease bolt. Figure 45— Power Spring Compressing Fixture Figure 46— Breather Assembly CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 259 Cover assembly from fixture. with plastic tape until sealer sets. 12. Install hex nut and snap ring on release bolt. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 260 7. Replace diaphragm 8. Brake shoe anchor pins frozen 8. Free up, replace or lubricate as necessary Foot control valve linkage improperly adjusted 9. Adjust Lubricate or replace Camshaft bushings binding or worn CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 261 3. Faulty compressor this manual) 4. Open or leaking reservoir drain cocks. 4. Close, repair or replace. 5. Defective compressor governor 5. Repair or replace CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 262 1. Adjust 1. Safety valve out of adjustment 2. See chart on "A i r pressure above normal” 2. Pressure in system above normal 3. Adjust 3. Governor out of adjustment CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M ANUAL...
Page 263 3. Plunger seal failure 3. Replace seal; clean and lubricate actuation parts 4. Adjusting bolt threaded into actuator too tight 4, Back off bolt 1/4 turn 5. Plunger guide washer omitted 5. Replace washer CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 264 3. Adjust brake shoes 4. Improper wedge adjustment 4. Make wedge adjustment 5. Plunger seal failure 5. Replace seal and clean and lubricate actuation parts 6. Grease on linings 6. Reline brakes and check seals CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 265 % " Crescent :> k'' Crescent Area (sq. in. per a x le )........................Brake Chamber Standard Diameter (at clamp band)......................5.66" 5.66" Fait| Safe Diameter (at chamber body)....................... 5.264" 5.264" CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 266 BRAKES 5B-73 Proper preventive maintenance on a regular daily, monthly, and yearly basis will help eliminate ”on-the- road" failures. Follow recommended procedures cover ing testing, inspection and adjustment for best results. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 267 4. Remove lock wire from anchor screw, then _______ TPM-9873 back screw out until clear of anchor bar. 5. Slide band and lining assembly straight to Figure 1 — Contracting Band (External) Parking Brake (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 268 4. Expand shoes by rotating adjusting screw with screwdriver inserted through hole in drum. Move outer end of screwdriver away from drive Figure 2 — Internal Expanding Type Brake Adjustment CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 269 Remove propeller shaft flange at mainshaft 11 Support Plate _____ TPM-8399 as directed in "T R A N S M IS S IO N " (SEC. 7B) of this manual. Figure 3— Internal Expanding Type Brake Installed CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK 5HOP MANUAL...
Page 270 When Stopmaster brakes with the refer to "Stopmaster Brakes" in "A IR B R A K E S" "Fail-Safe" feature are useda£ optional equipment, (SEC. 5B) of this manual. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 271 Total Lining Area (Sq. I n . ) ..67.5 99.1 126.0 60.7 Proper Adjustment and Periodic Inspection and Test ing of All Parking Brake Components is Essential to Satisfactory Performance as Well as Basic Safety. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK. SHO P MANUAL...
Page 272 " F U L L ," the lower " A D D " or "A D D O I L ." Keep level as close as possible to " F U L L " markwithout over-filling. Do not operate with level below " A D D " CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 273 C A U T IO N : When using remote switch to oper ate starter, the primary wire must be disconnected ders does not increase compression, the cause CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 274 If voltage reading is less than 9 rocker arm covers. volts when engine is being cranked, or if cranking 2. Referring to figure 4 use torque wrench to CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 275 5. Refer to EN G IN E E L E C T R I C A L (SEC. 6Y) for instructions for checking voltage and current regulator settings, generator output, and specifi Figure 5— Cylinder Head Bolt Tightening Sequence on V-6 Engines cations on various electrical equipment units. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 276 6). Remove breather cap (3, fig. 6). Inspect breather cap and if it is clogged wash element in cleaning solvent. Figure 6— Schematic Diagram of Crankcase Ventilation System on V-6 Engine CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 277 15. The hydraulic clutch release cylinder line previously and need not be repeated. should remain attached to cylinder, the cylinder CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M ANUAL...
Page 278 Use spark plug gasket and in keys. Continue to turn the stud nut until spring is stall adapter (J-21546) in spark plug hole. compressed sufficiently to permit removal of the CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 279 Do not pry on cover flange since the flange may be distorted. Figure 9— Sectional View of Cylinder Head CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 280 IN T A K E M A N I F O L D from tilt cab model, the transmission control rods Remove air cleaner or adapter and hoses must first be removed. from carburetor. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 281 4. Install exhaust manifolds using new gas kets and bolt locks. Tighten exhaust manifold bolts to 15 to 20 foot-pounds torque. Connect Figure 11 — Cylinder Head Bolt Tightening Sequence exhaust pipes to manifolds „ CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P MANUAL...
Page 282 2. Use impact wrench, or hold engine flywheel and use conventional wrench to remove pulley re taining bolt. Figure 14— Tool for Installing Pulley Figure 13— Crankshaft Pulley Hub Removal (TypicalI or Hub on Crankshaft (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 283 4 G a s k e t s 3 Key Figure 16— Front Cover Oil Seal Installation Figure 17— Oil Pump Installation on Engine (With Cover Installed on Engine) Without Hydraulic Governor CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 284 6 Flywheel Housing r .,m, 3. Install drain plug with new gasket, then fill 'F U L L ” mark on dip crankcase with engine oil to stick. Figure 19— Tachometer Drive Installation CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 285 No. 1 exhaust valve as en front cover assembly, then align marks on sprock gine is cranked slowly. When push rod rotates with ets or gears. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P MANUAL...
Page 286 Drain oil from oil pan and remove oil pan or replaced. from engine. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 287 2 0 - 2 5 Oil Pump to Block B o l t s ........ 3 0 - 3 5 * Oiled with S .A .E . No. 10 Engine Oil. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P MANUAL...
Page 288 3. Clean or replace and adjust spark plug gap. 3. Faulty spark plugs. 4. Inspect wiring and correct as required. 4. Defective wiring. 5. Set ignition timing. 5. Ignition out of time. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 289 2. Air cleaner restricted. 2. Service air cleaner. 3. Carburetor float valve not seating. 3. Clean float valve and set float level. 4. Rich mixture at idle speed. 4. Adjust carburetor idle mixture. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 290 1. Adjust idle mixture screws. 2. Improper ignition timing. 2. Set timing. 3. Vacuum leak (air entering intake manifold). 3. Replace gasket, or tighten manifold bolts. Check and/or replace vacuum brake hose (when used). CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 291 3. Drain crankcase and refill to correct level. 4. Crankshaft oil seals worn. 4. Replace oil seals. 5. Pistons and/or rings worn, or pistons damaged; cylinder bores scored or worn. 5. Overhaul engine. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 292 N O T E : When diagnosing engine noise problems, be careful that noises caused by accessories such as air compressor and power take-off are not mistaken for engine noises. Removal of accessory drive belts will eliminate any noises caused by these units. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M ANUAL...
Page 293 V E N T I L A T IO N UNITS A N D O IL F IL T E R S R E G U L A R L Y . CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 294 N O T E : Belts used in pairs 2. Remove shell and element as an assembly must be replaced as a matched pair even though by removing bolt which is threaded into filter base. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 295 Slipping will occur if drive belts are and return line between engine and fuel tank, for not adjusted tight enough. Belt life will be shorten evidence of leakage. ed if belts are not properly tightened. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 296 When the feeler gauge is removed both valves will have their proper clear Figure 2— Cylinder Numbering and Firing ance. Order 6V-53 Diesel Engines CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 297 6. Disconnect light wiring harness. Remove out of vehicle. hood assembly, then remove grille brace bolts and Figure 3 is view inside cab with engine cover support bracket bolts. Remove grille assembly. and transmission cover removed. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 298 An exhaust valve spring may be removed, without removing cylinder head from the engine, as follows: Figure 4— Use of Special Tool for Removing Valve ■ 1 . Remove valve rocker cover. Spring with Cylinder Head Installed CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 299 10. Loosen hose clamps, then move hoses as 6 — Fuel Rod and Installation t ig u r e L in k CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 300 E N G IN E F U E L S Y S T E M (SEC. 6M) of this manual, for instructions. Check push rods to see that each one is threaded completely through clevis, Figure 9— Cylinder Head Bolt Tightening Sequence CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 301 200 to 220 4. Clean the oil pan with a suitable solvent; foot-pounds torque. dry the oil pan. 6. Install belts, radiator and sheet metal. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 302 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 303 The pocket through a passage into the flywheel housing. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 304 BLOWER NOT FUNCTIONING—Check blower drive shaft and couplings. EMERGENCY SHUT-OFF VALVE PARTIALLY OR COMPLETELY CLOSED-Reset. FUEL AIR LEAKS, FLOW OBSTRUCTION, FUEL PUMP-Refer to “No Fuel or Insufficient Fuel” chart. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M AN U AL...
Page 305 IMPROPER GRADE AND TYPE FUEL-Refer to Current Diesel Service Bulletin. DILUTED FUEL—Check storage and handling methods. IMPROPERLY FILTERED OR RESTRICTED FUEL FLOW-Refer to “No Fuel or Insufficient Fuel” chart. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 306 4. Blower Air Intake Obstructed—Check and clean air cleaner and air inlet horn and screen. 5. Excessive Exhaust Back Pressure—Inspect exhaust pipe and muffler and replace if damaged. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SHOP M A N U A L...
Page 307 MIS-FIRING CYLINDERS—Check for the following: 1. Faulty Injectors—Replace injectors. 2. Low Compression—Refer to “Hard Starting” chart. 3. Low Cetane Fuel—Refer to Current Diesel Service Bulletin. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 308 OIL COOLER CORE LE AKIN G—Replace oil cooler core and use a good cooling system cleaner to remove oil from water passages. ENGINE BLOCK END PLATE GASKETS LEAKING—Replace block to end plate gaskets. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN U AL...
Page 309 EXCESSIVE WEAR OF CRANKSHAFT BEARINGS—Change engine bearings, clean oil pan, refer to “Engine Oil Viscosity Chart” for proper grade, and change oil filter element. GALLERY, CRANKSHAFT OR CAMSHAFT PLUGS MISSING-Replace plugs. CHEVROLET SERIES 70-80 H E AV Y DUTY TRUCK SH O P M A N U A L...
Page 310 BLOWER OIL SEAL LE AKIN G—Remove and overhaul blower. EXCESSIVE EXHAUST BACK PRESSURE EXCESSIVE MUFFLER RESISTANCE—Repair or replace muffler. OBSTRUCTION IN MUFFLER-Repair or replace muffler. EXHAUST PIPING—Replace damaged pipes. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 311 Thermostat Housing Vent Holes Plugged—Clean. BELOW N O RM AL POOR CIRCULATION—Check for the following: 1. Thermostat Inoperative—Replace thermostat. Thermostat Seat Damaged—Replace thermostat. Thermostat Seal Damaged—Replace seal. CHEVROLET SERIES 70-60 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 312 130-180 T V 70 80-120 130-180 Bolt T V 70 55-75 55-75 80-120 Bolt T M 80 55-65 35-40 T M 80 60-70 60-70 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 313 Figure 3— Engine front M ounting Assy, for V -6 Engines the attaching bolts and nuts to torque specified in (Show n w ith M ounting Cushions Rotated 90°) torque chart on previous page. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 314 9 Bolt and Lock Washer 5 Mounting Lower Cushion T-l 148 Figure 4— Engine Rear M ounting for V -6 G asoline Engines T ilt Cab M odels CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 315 Be sure all bracket attaching bolts are kept tight. Figure 6 —Engine Rear Mounting (6V-53 Engine) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 316 From slowly, allowing a gradually increasing amount of Figure J — Coolant Circulation (V-6 Gasoline Engine) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 317 As engine reaches THERMOSTAT HOUSING OVERHEAT ALARM BY-PASS TUBE l/ ■ THERMOSTAT HOUSING TEMPERATURE GAUGE SENDING UNIT Figure 2 — Coolant Circulation (6V-53 Engine) CHEVROLET SERIES 70-80 H E AV Y DUTY TRUCK SH O P M A N U A L...
Page 318 When cold water is poured into the radiator, solution as follows: the thermostats will close even though the engine CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 319 Correct cause of leakage, then install condition and will make an airtight seal. Adjust thermostats and adjust drive belt. Fill radiator. level of cooling liquid in radiator, allowing ample CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 320 — Engine U nits for Overheat Sw itch and 4. Remove test light and reinstall wire on Tem perature IV-6 Gasoline EngineI Gauge unit. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 321 Refer to "Specifications” for switch setting. following test should be conducted. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 322 Install drain 3,000 miles. After initial change, the filter should plug (5) in bottom of filter body. be serviced periodically 7,500 to 10,000 miles or CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 323 Oil cooler, located at bottom of radiator core, Figure 6— O il Cooler Circuit IA II M odels should be flushed in the following manner: Except w ith 6V-53 EngineI CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 324 6. Install air compressor drive belt (if equip sure fan blade does not contact shroud after ad ped). justment of drive belt tension. Shroud can be ad CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 325 Figure 9— Separately M ounted Fan Support Assem bly 16V -53 Engine) Fiaure 8 — Belt Adjusting M echanism s Engine) I 6 V - S 3 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 326 100 pounds for used belt). Tighten locking bolts. — W ater Pum p D rive B elt Idler Pulley Figure 10 Assem bly 16V -53 Engine) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 327 EN G IN E O V E R H E A T SW IT C H Switch Contacts Close at: Gasoline E n g i n e s ........ 225°F Diesel Engines ........215°F CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 328 5. Release accelerator pedal. Connect pull- connect rod assembly at carburetor lever. bafck spring. 2. Disconnect sliding rod assembly at bell crank lever CHEVROLET SERIES 70 -80 H EAV Y DUTY TRUCK SH O P M A N U A L...
Page 329 5. Remove vise-grip pliers used to lock bell 1. Disconnect pull-back spring. Disconnect crank lever to mounting bracket. Install throttle Figure 3— Accelerator Linkage (TM80) CHEVROLET SER1D! 70 -80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 330 For service of air cleaners refer to “ L U B R I carburetor. If cleaner is allowed to become clogged, flow C A T I O N " (SEC. 0) of this manual. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 331 Fuel pump-to-engine attaching bolts should be Repairs can be made aftsr fuel pump is removed. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK S H O P M A N U A L...
Page 332 Diaphragm spring (4) holds dia- pump (1/2 engine crankshaft speed). At one end of CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 333 “ G O V E R N O R " covered pre system, the accelerating system, and the power viously in this group for governor operation. system. CHEVROLET SERIES 7 )-8 0 H EAVY DUTY TRUCK SH O P M AN U A L...
Page 334 Closing choke plate, CHEVROLET SERIES 70-80 H E AV Y DUTY TRUCK SH O P M AN U AL...
Page 335 Inlet Ball Check (Closed) (Open) VIEW E-ACCELERATING SYSTEM (DISCHARGE STROKE) VIEW F-ACCELERATING SYSTEM (RETURN STROKE) TPM-8357 -2 Figure 8— Carburetor Operation Views (401M and 478M Engines) (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 336 A L D A M A G E W IL L R E S U L T TO V A C U U M screw to allow idle speed screw to contact its ID L E S T O P U N IT. stop. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 337 IDLE MIXTURE SCREWS VIEW C T - 4 3 1 3 Figure 9— Bendix Slromberg Carburetor (W W C Series) Figure 11— Fast Idle Adjustment IW W C Series) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M ANU AL...
Page 338 . / j jmmmjfr BENDING LEVER TO RAISE SETTING BENDING LEVER TO LOWER SETTING Figure 13— Use of Bending Tool to Set Float Level CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 339 Figure S — Vacuum Idle Stop (Bendix-Strom berg Carburetor (W W C Series)1 Bendix-Stromberg carburetors used on V6 engines. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 340 P R E S S U R E M O D E L E N G IN E 1 pint in 20-25 seconds 6440050 5-6 1/2* *A t 1 6 " above outlet. CHEVROLET ScRiES 70-80 HEAVY DUTY TRUCK SH OP M A N U AL...
Page 341 ENGINE FUEL SYSTEM 6M -14 SPECIFICATIONS (CONT.) BEN D IX-STROM BERG CARBURETOR SPEC IFIC ATIO N S 655923 655924 GM P A R T NO. 2483900 658394 Venturi Size ..............1 5/16" 1 5/16" Main Discharge Jet N o............— Main Metering Jet Size ............
Page 342 Figure 2— A ccelerator Linkage for 6V-S3 Engine -Accelerator Linkage for 6V-53 D iesel Figure 1 on T ilt Cab M odels (TV-70) Engine (Conv. Cab M odels) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 343 Stamped , T-65 Figure Fuel Filter Engines) Figure 3 — Primary Fuel Filter (6V53 Engines) 4— Secondary (6 VS3 CHEVROLET SERIES 70*80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 344 (figs. 5 and 6) are of different design, the element replacement procedure is the A N D E X H A U S T (SEC. 8) of this manual. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 345 1. Creates the high fuel pressure required for efficient injection. 2. Meters and injects the fuel to the exact amount required to handle the load. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 346 *p 3®i2 Figure 3— Fuel M etering Positions From Figure — Phases of Injector O peration Through Vertical Travel of Plunger N o Load to Full Load CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U AL...
Page 347 A check valve, directly below the bushing, fuel under the plunger is subjected to increased prevents leakage from the combustion chamber CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 348 2. Rotate the crankshaft in the direction of engine rotation until the exhaust valves are fully depressed on the particular cylinder to be timed. Figure 7— Timing Fuel Injector CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 349 7. To be sure of the proper rack adjustment, (4) Injector fuel control racks in the F U L L the following check should be performed: F U E L position. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 350 5. If the cylinder is firing properly, repeat 4. Remove the two rocker shaft bracket bolts the procedure on the other cylinders until the CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M AN U A L...
Page 351 Remove the shipping caps. Then align the bushing and whether the control rack moves back fuel pipes and connect them to the injector and the and forth freely. CHEVROLET SERIES 70-80 H EA V Y DUTY TRUCK SH O P M A N U A L...
Page 352 5. A leak at the filter cap indicates a loose air. Then, pump up the tester and maintain a pres filter cap or a damaged filter cap gasket. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 353 Place the injector in the comparator, as shown in figure 14. Then, turn the wheel to clamp Figure 13— Position of Fuel Flow Pipes the injector and adapter J-7041-130 in position. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 354 The fuel pump, illustrated in figure 15, is the positive displacement gear-type. The pump circu- means of attaching piping for draining off any leak- CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 355 "c " following: the cylinder head and the fuel supply tank. c. Check fuel pump as instructed previously CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U A L...
Page 356 The letters D .W .- L.S. stamped on the 6V-53 governor name plate denote a double-weight limiting speed governor. Figure 18— Limiting Speed Governor Mounting CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 357 This is done by turning the high levers. speed spring retainer nut on governors with the CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 358 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 359 8. Recheck gap and readjust if necessary. possible and still eliminates the engine hunting. 9. Stop engine and reinstall governor cover. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 360 ENGINE FUEL SYSTEM 6M -33 Do not intermix the needle valve injectors with the other types of injectors in an engine. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 362 All procedures in this section apply Bendix-Westinghouse compressor used to optional as well as the standard equipment on some models is flange mounted at rear of en- compressors. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U AL...
Page 363 “ Drive Belt Maintenance and end of arm is attached with a nut and bolt to an adjusting arm bracket fastened to compressor. Adjustment.” CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 364 Figure 3 — Flange Mounted Compressor Drive coupling components. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 365 Lift air compressor 4. On water cooled models, make sure drain assembly off mounting bracket. plug is installed in compressor cylinder block. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 366 O-ring and back-up ring, in bore. 2. Slide plunger guide down over unloader follows: Figure 6 — Removing Unloader Components IB-W ) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 367 Un installation. If a new unloader is being installed loader should withstand a pressure of 100 psi omit the unnecessary steps. without leaking. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 368 Westinghouse air compressors. past the upper piston grommet (B-W only). there excessive leakage, overhaul R E M O V A L 1. Exhaust air from system. governor. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 369 14 Exhaust Stem Grommet 15 Piston 16 Valve 17 Valve Spring 18 Piston Grommet 19 Governor Body 9 3 < t p m Figure JO—Compressor Governor (B-W) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 370 280368 80 Series H M , JM Water Belt Paper N5903V Water Belt Paper or 281430 Paper Water Belt N5903G Paper Water Belt or 279580 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 372 Care must be taken to keep and battery hanger. vent plugs tight, so that the neutralizing solution All batteries having a one-piece cover (fig. 1) does not enter the cells. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M AN U AL...
Page 373 If the spec which the vehicle is used only for short drives. ific gravity reading of any cell fails to reach 1.250 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 374 9 Amps 40 to 40 to 50 Amps 2. Note the electrolyte level. Levels that are 50 Amos too low or too high may cause poor performance. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SHOP M A N U A L...
Page 375 C H A R G E H Y D R O M E T E R vigorous gassing. T E S T " previously on this page. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M AN U AL...
Page 376 Failure to do so may harm the battery. to increase the specific gravity of the electrolyte. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 377 10.5 Min. at 300 A m p . 1980760 8DR-205 6.0 Min. at 300 Am p. 3H-926 1980926 2.8 Min. at 300 Am p. 9H9-974 1980974 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 378 N O T E : To make these checks on gasoline Figure 1 — Voltmeter Connections For Checking Circuits engine models, disconnect the primary lead at the CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 379 Figure 2— Starter Automatic Disengagement of the solenoid linkage or shift lever yoke lugs. and Lock-Out (Series “53 ” and Diesel) (Typical) CHEVROLET SERIES 70 -80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 380 As soon as plung Figure 4— Measuring Pinion Clearance (Light er closes the main switch contacts, pulling winding and Intermediate Duty) (Typical) CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 381 ENGINE ELECTRICAL 6Y-10 can be checked for current draw, open circuit, or shorts. Refer to "Specifications" at end of this section for current values. Solenoid coil, terminals, and switch plunger can be replaced if burned or otherwise damaged. Whenever solenoid is replaced on overrunning clutch type starting motors, pinion clearance must be checked and adjusted, as pre...
Page 382 CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 383 No. 1 wire socket in cap. Remove distributor cap. 2. Intermittently operate starter until proper timing mark on crankshaft pulley is aligned with pointer (fig. 2). Figure 2— Timing Marks IV-6 Engines) (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 384 5. Clean breaker plate of oil, smudge and dirt. Figure 4 — Breaker Plate and Attaching Parts Figure 3— Distributor and Ignition Coil Installed ITypicalI CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L R evised 1968...
Page 385 Contact points must be set to the proper open ing. Points set too close may tend to burn and pit Figure 5— Checking Breaker Arm Spring Tension CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 386 3. Disconnect the distributor primary wire from terminal on ignition coil. 4. Intermittently operate starter until crankshaft pulley comes to rest with the 10 BUDC Figure 6— Setting Point Opening CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 387 Spark plug failure, in addition to normal wear, elements of condenser. This condition prevents may be due to dirty or leaded plugs, excessive any condenser action. gap, or broken insulator. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 388 (preignition) of the fuel Figure 7— Wrench Socket Installed on Plug (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 389 (3 ) Specifications listed are distributor degrees and distributor RPM which are one-half engine degrees and engine RPM. (4 ) Plus or M inus one degree CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U A L...
Page 390 A voltmeter is available as optional equip erating system used on vehicles equipped with the ment. 1116374 or 1116378 regulator. CHEVROLET SERIES 70-80 H E A V Y DUTY TRUCK SH O P M A N U A L...
Page 391 WITH 1116378 REGULATOR T - 4 4 2 1 Figure 2 — Schematic D iagram of A.C. C harging Circuit (with 1116374 or 1116378 Regulator) (Typical) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U A L...
Page 392 5. Check battery electrolyte level and replen same time. Belts are available in matched sets ish as necessary. Check specific gravity also. only. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 393 Lift brushes off slip rings and spin drive CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 394 System Trouble Analysis Chart" later in this sec tion to determine whether something other than a Figure 5 — Connections for Testing Generator generator defect is indicated before proceeding. Output CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 395 2. Connect an ammeter and a 1/4-ohm resis Figure 8— Testing Voltage Setting tor with a rating of 25 watts or more in series in (Two-Unit Type Regulator) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 396 ENGINE ELECTRICAL 6Y-25 9. Operate engine at approximately 2500 rpm and note voltage setting. Readjust if necessary. 10. Check the voltage setting while operating on the lower set of contacts as follows: Slowly increase the resistance of the variable resistor with the engine operating at 2500 rpm until the regulator begins to operate on lower set of contacts.
Page 397 0.3 Figure 10— Connections tor Testing 1116374 or volts, then check the battery over a period of time 1116378 Regulator Voltage Setting ITypicalI CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK. SH O P M A N U A L...
Page 398 4.-Remove adjusting arm pivot bolt and gen to be sure all leads are properly connected. Install erator to mounting bracket bolts; then remove cover over brush holder. generator. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 399 These surfaces should be cleaned to bare metal with #400 silicone carbide paper Figure 13— Adjusting Point O pening Figure 14— Adjusting Air Gap CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 400 Instructions for The point opening can be adjusted by bending making final setting are explained previously. See the relay heel iron. "Regulator Voltage Test (On Vehicle).” CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 401 Figure 17— Full Transistor Type Regulator (Model 1116374 or 1116378) (Typical) connector and the regulator. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 402 Check by attempting to pull connector apart. in limits listed in "Specifications" at end of this 3. Connect battery cable to battery terminal. section, repair or replace the regulator. CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 403 ENGINE ELECTRICAL 6Y-32 TROUBLE ANALYSIS CHART CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 404 Rear B ra c k e t ..................Bolt 45-55 Front B ra c k e t..................Bolt 30-35 40-50 T ilt Cab M odels ..................Bolt CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 405 Point Opening ( I n . ) ............Closing Voltage R an g e ................2.5-3.5 10 Max. Sealing Voltage Range................0-1 Volt- above closing CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 406 (see Inset, fig. 1) at either the LU BR IC ATION (SEC. 0) of this manual. Figure 1— Typical Tilt Cab Transmission Control Linkage CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 407 F U L L Y remove remote control assembly, keeping the assembly slightly tilted to the left, as shown, Figure 2 — Typical Control Island Shift Mechanism CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 408 Shift Rail 16 Snap Ring 9 E xpan sion Plug TPM-9143-1 Figure 4 — N e w Process 5 40 and 541 Remote Control Assem bly CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 409 9 Snap Ring 19 Oil Seal 29 Shift Lever Mounting Bracket 10 Lock Washer 20 Breather Assembly T-992 Figure 5 — Clark Remote Control Assem bly CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 410 (23) to control housing (3), then remove reverse shift finger. Figure 6 — Spicer Remote Control Assem bly CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 411 T V mechanism in the trans mission may be sticking. The through-detent posi 4. When transmission performing properly. tion should not allow transmission to upshift and CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U A L...
Page 412 (A) 0.060 inch from stop (B), nuts located on either side of the cab floor (see Figure 8 — Accelerator and TV Linkage (V -6 G as Models) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 413 To raise shift point, shorten rod (F) until linkage, adjust engine idle speed to 500 rpm and the desired shift point is obtained. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK S H O P M A N U A L...
Page 414 Figure 12—Adjusting Master Cylinder Push Rod (Typical for Conventional Cab) Figure 11 — Retarder Controls (Conventional Cab Models) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 415 " O F F " position (retarder valve fully closed) when the pedal is released. The pedal must return positively and Figure 13— Ref order Controls ITM 80! CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 416 In numerous instances, drivers have insisted 2. Hissing, or more serious a thumping or that the noise was in the transmission, however, bumping-type noise. Hissing noises could be CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 417 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 418 6. Improper adjustment of shifting linkage or without using the clutch will burn or wear out excessively worn. manual synchronizers at relatively low mileage. 7. Worn shift rods. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 419 On tilt cab models, disconnect shift linkage transmission replacement. from remote control assembly at transmission. It is important to note that vehicles covered CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 420 Figure 2— Replacing Gearshift Lever CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 421 (SEC. 4D) of this manual. 6. Remove mainshaft rear bearing cap and gasket. Discard gasket. 3. Remove parking brake (when used) from CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 422 New Process 540 or 541 ....... 130-150 Clark 385V or 3 8 7 V ......550-600* Spicer 5652 or 5752 ......500-550 ♦Secure with new cotter pin. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 423 Tower Tower Shift Transmission | Shift Rod CONTROLS AT TRANSMISSION CONTROLS AT SHIFT TOWER TPM 9 152 Figure 1— Typical Auxiliary Transmission Linkage Adjustment CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 424 VIEW C-FRONT MOUNT SPICER 7041 FRAME 190-210 FT.-LBS. : 310-330^FT.-LBS. CROSS BEAM REAR MOUNTING BRACKET VIEW F-REAR MOUNT SPICER 6041 AND 7231A T-3065 Figure 2 — Auxiliary Transmission Mountings CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 425 5. Reconnect parking brake linkage (when used). 1 / 2"-20 Bracket Bolt 1-7/8" 45-55 6. Connect speedometer cable to adapter at the 2" 70-80 rear of the transmission. 5/8"-18 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 426 View F, Fig. 2 3-1/8 JM80 478M C L401V SP7231-A View A, Fig. 2 3-3/16 Always Be Sure The Auxiliary Transmission Is Properly Mounted As Indicated Previously. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 428 Master cylinders used on models covered in Figure I — Clutch Hydraulic System (Typical for Conventional Cab Models) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 429 Brake M aster Cylinder Figure 5— Access to Master Cylinder Slave Figure 4 — Cylinder Push Rod Clearance (Tilt Cab Models— 70) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK S H O f M A N U A L...
Page 430 Figure 8— M aking Master Cylinder Push Rod Adjustment Figure 6— Clutch Pedal and Linkage (Tilt Cab Models— 70) (All Conventional Cab Models) (Tilt Cab Models— 70) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 431 Bleeder valve is provided at the slave cylinder (fig. 12). Figure 9— Push Rod Clearance Checking Tool CHEVROLET SERIES 70-80 HEANfY DUTY TRUCK SH O P M A N U A L...
Page 432 Clutch pedal should be pumped up and down slowly, Conv. Cab and Tilt Cab Models— 70) CHEVROLET- SERIES 70 -80 H EAVY D U T Y T R U C K S H O P M A N U A L...
Page 433 IM P O R T A N T : Make sure that bolt is inserted relationship is fixed, no push rod adjustment is in direction shown. required. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 434 -1 0 0 7 MASTER CYLINDER REPAIR Figure 15— Master Cylinder Fillers Cap Baffle (Tilt Cab Models— 80) The following procedures cover disassembly, CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M A N U A L...
Page 435 3. Remove bolts retaining slave cylinder at Figure 16— Master Cylinder Pedal Stop Adjustment mounting, then remove cylinder assembly. (Tilt Cab Models— 80) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 436 N O T E : Clutch Troubleshooting information is covered at rear of " C L U T C H E S ” (SEC. 7E). CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 437 The following procedures apply to all clutch stud after the assembly is removed from vehicle. components with exceptions as indicated. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 438 Check L U B R IC A T IO N (SEC. then drive shaft out of yoke and remove from the 0) for proper interval on the release bearing. housing. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 439 6. Check cross shaft and yoke to make sure they properly centered, then tighten yoke Figure 4—-Clutch Cover Hold-Down Bofi Locations clamp bolts. (Lipe— Rollway Clutch) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U AL...
Page 440 Be sure the wood blocks (fig. 3) or hold- down bolts and washers (fig. 4) are installed in the Figure 6— Clutch Release Mechanism (Yoke Type) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 441 (when used) to the clutch housing. " C L U T C H C O N T R O L S ” (SEC. 7D). CHEVROLET SERIES 70-80 H E A V Y DUTY TRUCK SH O P M A N U A L...
Page 442 1. Clutch master cylinder leaks past primary cup. 2. Tighten all line fittings and check for leaks 2. External leaks. in line. R e v is e d 1 9 6 8 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 444 Figure J— Tank Siphon Construction CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 445 T U B E \ '• ■ - S T O P PLATE Figure 2 — Tube Flaring Tool J-8051 Figure 4— Flaring Operation Positioning Tubing CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 446 When the position of the slider arm varies due to float action, a change in rheostat resistance occurs which results in a Figure 7— Gasoline Sending Unit (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 447 If wrong 7. Connect fuel line(s) at tank unit. Connect fuel gauge components are installed, inaccurate fuel electrical wire to terminal on tank unit. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 448 * Ignition switch must be " O F F " before removing tank sending unit, otherwise full battery voltage may des troy unit or ignite fuel vapors. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U AL...
Page 449 3. Increased fuel consumption. be experienced. 4. High engine temperature. 5. Possible severe damage to engine combus Exhaust gas from Diesel engines is considered tion chamber components. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 450 W A R N IN G - CA RB ON M O N O X ID E Keep cowl vent and heater intakes closed when operating in congested traffic to prevent deadly exhaust gases from entering cab. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 452 Before adjustments are made to the steering for adjustment of worm thrust bearings. Packing gear in an attempt to correct such conditions as CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 453 0 Pitman Shaft 31 W orm Shaft 1 Pitman Shaft Oil Seal 1 2936 Figure 1 — Type 553-D and 554-D Steering Gear (Typical) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 454 Filler Plug 26 Pitman Shaft Worm Upper Bearing 27 Drain Plug T - 2 9 5 3 Figure 2— Type 568-D Steering Gear (Typical) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 455 3. Refill gear housing with lubricant specified Figure 6— Steering Gear Adjustment Points Figure 4 — Checking Steering Wheel Rim Pull (Typical! (Type 568-DJ (Typical) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 456 VIEW A -N O N -A D JU ST A B LE TYPE DRAG LINK -COTTER PIN ■iyfi BALL VIEW B— ADJUSTABLE TYPE DRAG LINK END PLUG SEAT SPRING SPRING SEAT T-4464 Figure 7— Steering Drag Link Assemblies (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 457 L U B R IC A T IO N Figure 8— Steering Connecting Rod Assembly (Typical) (SEC. 0) of this manual. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK S H O P M A N U A L...
Page 458 If tie rod is not in alignment with the stud, binding 3. Lubricate tie rod ends as directed in L U BRICATION (SEC. 0) of this manual. will result. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 459 (8), dust cork (7), and dust cork arm and idler lever. washer (2). 2. Install stud nuts and tighten to torque listed CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 460 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 461 W H I L E V E H IC L E IS M O V IN G . Figure 13— Tilt Column Quick Release Mechanism CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 462 19 Wiring Harn ess Assem bly 11 Upper Shaft Assem bly Figure 15 — Steering Column and Shaft Removed fConv. Cab Modell (Typical) CHEVROLET SERIES 70-80 H EAVY D U T Y TRUC K S H O P M A N U A L...
Page 463 4. If used, remove trailer brake hand control Figure 17— Steering Column Upper Shaft Lower Bearing IConv. Cab Model) (Typical) valve from steering column. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 464 10 Cork Washers 11 Yoke Shaft Bushings 12 Snap Rings 13 Lube Fitting 14 Yoke Shaft Center Cross 15 Clamp Yoke Figure 19 —Intermediate Shaft Components (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 465 This steering gear worm shaft with match marks align is an important safety procedure which will pre vent internal steering shaft joint interference. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 466 Pitman shaft nut. Tighten nut to torque speci fied in "Specifications" at end of this section. Figure 2 0 — Pitman Arm Installed (Conv. Cab ModelI CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M A N U A L...
Page 467 *T ig h te n to S p e cifie d T o rq u e , T h e n A d v a n c e to N ext A lig n in g S lo t and In sta ll N ew Co tter P in. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 468 STEERING SYSTEM 9B-17 SECTION 9B POWER STEERING GENERAL The power steering system is a complete in line unit. The steering shaft, hydraulic valve, The power steering system provides automatic worm, and ball nut are in a line, making a com hydraulic assistance to the turning effort applied pact, space-saving steering gear.
Page 469 N O T E : When hydraulic fluid is added to power Figure 3— Checking Pump Hydraulic Pressure steering system, fluid should be poured through a (Vane Type Pump) (Typical) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 470 (new belt) or 90-100 pounds (used belt) is obtained on a strand tension gauge. Figure 4 — Checking Pump Hydraulic Pressure 3. Tighten pump to mounting bracket bolts. (Slipper Type Pump) (Typical) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 471 23 Back-up Washer 24 Worm Bearing 25 Worm Oil Seal TPM-9060 Figure 5 — Power Steering Control Valve (Type 5 S 3 D V I (Typical) CHEVROLET SERIES 70-S0 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 472 4. Attach intermediate shaft clamp yoke or driving range of wheel effort and will retain the coupling to steering gear worm shaft with bolt, "road-feel necessary for effortless driving." CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 473 These causes and remedies are given in the "Trouble extremely the replacement objectionable, since Shooting Quick Reference Chart" later in this sec valve will also have a slight "hissing" noise. Be tion. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U A L...
Page 474 Hole >le H< Hole Crossover Hole Figure 6— Power Steering Hydraulic Pump Installed (Typical) in Pump Figure 7— Cross Section Rotor and Vanes Body CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 475 V IE W B - P U M P O P E R A T IO N -H IG H SPEED T-l 166 Figure 8— Power Steering Hydraulic Pump Operation CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 476 Refer to LU B R IC A T IO N (SEC. 0) for type of in raised position to prevent drainage of oil. fluid to be used. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 477 Refer to next page for Hydraulic Pump Troubleshooting Procedures. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 478 This may be determined wheel stop for an extended period of time, there by two tests after placing a pressure gauge in the fore, the oil will overheat. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SHOP M A N U A L...
Page 479 Cover hose fittings and ports in cylinder. Figure 10— Power Cylinder Oil Flow (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 480 4. Reconnect hydraulic hoses to power cylin end ball stud seats, and adjuster screws. Figure 12— Axle Mounted Power Cylinder Adjustment (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 481 1. At each end of the tie rod, remove cotter CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 482 STEERING SYSTEM 9B-31 pin and stud nut. Discard cotter pins. 2 . Tap tie rod loose from steering arms. 3. Remove two cupped metal washers and rub ber washer from each tie rod end stud. Discard these parts. IN S T A L L A T IO N 1.
Page 483 S c o r e d p re s s u re p la te, th r u s t p la te , a n d / o r rotor. L a p a w a y lig h t s co rin g . R e p la c e h e a v ily s co re d p arts. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 484 . CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 485 T o rq u e to s p e c ific a tio n s a f t e r p ro p e r p o s itio n in g to s p e c ific a tio n s . clam p movement. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 486 Minimum ( p s i ) ..........................1000 Maximum (p si)..........................1100 POWER STEERING POWER CYLINDER Make ......Saginaw Steering Gear Division T y p e .................Hydraulic Length and S t r o k e ......See chart following CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 487 Stu d * With F-160 Front A x le ....125-150 and Install a New Cotter Pin to Secure. R.H. Idler A rm — With F-160 Front Axle Support Bracket to Frame B o lt ..... 50-60 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 488 Wheel hub flanges should be clean and free of Figure 1— W heel N ut Tightening Sequence for Cast W heels Figure 2— W heel N ut Tightening Sequence for 1 0 H ole W heels CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 489 Wheels that are distorted in excess of these limits should be replaced. N O T E : Additional instructions on balancing wheel tire assemblies are included under "Wheel and Tire Balancing” later in this section. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 490 The valve cap is provided to seal the air in the tube Figure 4— Tire Rotation D iagram and tire. When valve cap is tightened down on stem, CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 491 Bent wheels that have runout over 3 /3 2 " should seated, then remove safety bar. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 492 5480 11.00-22 (For Single Tire Application O n ly — -6900 Lbs. Load @ 100 psi) 11.9 -20 Bold face figures indicate m axim um recommended load. N O T E : CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 494 1. Raise and support hood side panels. 2. Disconnect head lamp wiring harness con RADIATOR SHELL DISCONNECT POINTS CORE SUPPORT UPPER BRACKET Figure 2— Radiator Shell Replacem ent Figure 1— Front End Components CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 495 6. Remove bolts which attach the radiator shell brackets (right left) to the flexible Figure 4— Radiator Shell Flexible M ounting mounting as shown in Figure 4. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 496 IN S T A L L A T IO N Assemble fender and skirt if necessary, then install fender assembly in reverse of "Removal" Figure 5— Radiator Shell Strut Rods procedures. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 497 T W O A T T A C H IN G BOLTS A N D NUTS Figure 9 — Hood Center Panel Mounting CHEVROLET SERIES 70 80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 498 IN S T A L L A T IO N The following describes procedure for re Install the hood assembly in reverse of the placing the complete hood assembly which includes "Removal'' procedure. the right and left, and center panels. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 500 SECTION 12 CHASSIS ELECTRICAL AND INSTRUMENTS This group, covering maintenance of chassis electrical system and units, is divided into sections as shown in the index following. Section Page No. Miscellaneous Electrical............12-1 Alarm System................12-5 Instruments and G a u g e s ............12-5 Lighting System................
Page 501 Pull wire and term inal from cable connector. Terminal Installation N O T E : If original terminals are to be used, Figure 2 — Removing Twin-Lock Connector Terminals CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 502 Replace cable if kinked or are mounted at left or right of dash panel inside broken. If the speedometer head, adapter and the cab. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH OP M A N U A L...
Page 503 3. Horn circuit is internally grounded through H O R N R E L A Y the horn mounting. Therefore, it is necessary that Refer to applicable wiring diagram for wiring CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 504 I M P O R T A N T : Disconnect negative battery strument lights, tell-tale lights, gauges, speed cable before removing the instrument cluster to ometer, and tachometer. prevent accidental grounding at ammeter. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 505 — T y p ica l Instrum ent C lu ste r (Se rie s 7 0 nv. C a b M o d e ls) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 506 Do not pry under edges of cluster at front this work must be performed by a competent elec- side of panel; this could damage the bakelite case. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 507 — R e m o v in g In stru m e n t C luster ITilt C a b M o d e l I fT y p ic a l) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 508 Especially in the case of vehicles carry ing widely varying loads during night-time oper Figure 11 —Headlight Beam Adjustment (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U AL...
Page 509 2. Remove two screws which attach the head lamp retaining ring to the mounting ring. Using a Figure 13— Single Sealed Beam U nit Replacem ent hooked tool, release retaining spring from slot in CHEVROLET SERIES 70 80 HEAVY DUTY TRUCK SHOP MANUAL...
Page 510 Position lens and gasket on body sembly to front grille panel. Pull lamp assembly and attach with screws. from opening in grille panel. CHEVROLET SERIES 70 80 HEAVY DUTY TRUCK S h O ? MANUAL...
Page 511 DOME LIGHT On conventional cab models, dome lamp is 16— M ain Lig ht Sw itch mounted on instrument panel and provides lighting Figure CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P MANUAL...
Page 512 When brake is applied and pedal lever moves away from switch plunger, a spring within the switch moves the Figure 17— Main Light Switch Circuit Diagram CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 513 The same procedure applies to the Figure 18— D irectional Signal Light and Side M arker left-hand signal, except that lever is in the down CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 514 Figure 20— D irectional Signal Control Assem bly Figure D irectional Signal Control Assem bly (w ith H azard W arning Sw itchl 19— CHEVROLET SERIES 70 -80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 515 Closing Voltage........Adjust to Buzz At 0.25— 0.35 Am pere At 1 3 .5 -1 4 .5 Volts. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 516 Voltmeter Tell-Tale L ight............55 or 57 1 or 2 * L o n g Life U nit CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 517 T R iN S i | l » » I m' o o BL K. j[ l c R iM f g r d engjne > > l/> Figure 21-C a b , Engine, and Chassis Wiring— H V /JV 70 Sheet 1 of 6...
Page 518 CHASSIS ELECTRICAL A N D INSTRUMENTS 12-19 CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 519 )— o - v y v ^ — F U E L G A U G E f u e l TANK UMT ENGINE A LA R M ENGINE A LARM R P 0 .X 5 4 p in k — - -------- 0 U Z Z E R (R P O .) •...
Page 520 MARKER LIGHTS TRAILER CABLE RP0.-U 85-U 8 7 d ire c t ion a l - h a z a r d s t o p LIGHTS W iring— HV/JV70 Figure 21— Cob, Engine, and Chassis Sheet 4 of 6...
Page 521 CIRCUIT IDENTIFICATION Figure 21— Cab, Engine, and Chassis Wiring— H V /JV70 Sheet 5 of 6...
Page 522 LEGEND J U N C T I O N □ TfRM . CAVITY (*: th R U * >6) i h ' j TERM.JCT. STUD-INNER ( - E N G COMPART MCNT - DASH P A N EL-U P P ER R K S O E —...
Page 523 Figure 22— Cab, and Chassis W iring— TV70 Engine, Sheet 1 of 6...
Page 524 CONTROL SWITCH IN S T R U M E N T S and Chassis W iring— TV70 Figure 22— Cab, Engine, Sheet 2 of 6...
Page 525 CHASSIS ELECTRICAL A N D INSTRUMENTS 12-26 CHEVROLET SERIES 70-80 H E AV Y DUTY TRUCK SH O P M A N U A L...
Page 526 CH A SSIS ELECTRICAL A N D INSTRUMENTS 12-27 CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 527 CHEVROLET SERIES 70 -80 H E AV Y DUTY TRUCK S H O P M A N U A L...
Page 528 LEGEND FUNCTION S Y M B O L JUNCTION 8 WAY MULTIPLE CONNECTOR (BLK) 1NSTR PANEL HARN.T0 ENG HARN P > ] 0 WAY MULTIPLE CONNECTOR(WHT^ - - - C A B J C T B E L O O O R S T E P RISER w f l <§>...
Page 529 BA’"’ t p/ EN G G R G A f W E T E R - R P O '3 ; S T A R T E R V O L T M E T ^ - P D C. U K M i G S w w „...
Page 530 CHASSIS ELECTRICAL A N D INSTRUMENTS 12-31 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 531 LOW A iR A L A R M B U Z Z E R ENGINE A X 5 4 HORN Ht ING marker lights T R l IC.C. MKR LP R E L A Y LISE WITH SEW t T R L BRK E CONTROL R.PO J9l TRAILER CA8LE R P 0 - U 8 5 - U 8 7...
Page 532 OiRECTtONAL-HAZARD STOP LfGHTS E L E C . 2 S P D A X L E (W H EN U S E D ) BACK- UP L PS. Figure and Chassis H .D . W iring— TV70 23— Cab, Engine, Sheet 4 of 6...
Page 533 S P D W/S W IPER d u a l & W A SH ER E M E R G E N C Y A IR BPKE R P C J'7'’ H E A T E R i * B L U f H OffAN(,t ■...
Page 534 L E G E N D FU N C TION L O C A TION JUNCTION SY M BO L 12 POST JCT BLOCK L h ( * \ THRU*I2) C A B JC T B E L O W F L OO R AT LH FRT S TE P R lS T ER - INSTR PAN ELHA RN .TO ENG HARN.
Page 535 GRD.-CAB-ALL M O D E LS X0 8 L K ---- 1 | - ENG-N£ GRD.-ENGNE-FRAME MTD. BAT. t r a n s iff----- ? * ---- - { l * prame R.P0. Figure 24— Cab, Engine, and Chassis Wiring— H M /J M 8 0 Sheet 1 of 6...
Page 536 GENERATOR IGMTION-GAS MODELS CONTROL SWITCH TEMPERATURE GAUGE Chassis W iring— HM/JM80 Figure 24— Cab, Engine, and Sheef 2 of 6...
Page 537 FUEL GAUGE DUAL FUEL TANK-R.PO. NQ7 ( GAS M O D E L S ONLY ) ENGINE A LARM R.P0.X54 DFFERENTIAL LOCK T E L -TALE TANDEM A XLE M O D E L S ) LOW AIR A L A R M BUZZER LIGHTING Figure 24—...
Page 538 ■ 6 ~ i _ - - ' .0 FRT MKR. i_P5. m a r k e r l i g h t s B L U t-S P A R E - - /— '6 B k . — C_j— ‘6 8L *. — 1 2 q e : ■...
Page 539 2 SPD. W/S W PER a -AiaSHER -1 8 LT. C R N . ------ 8 L - [ T ^ B A C K - U P L P S ..---- frv..". - l£ BLK.t R V U E D ! ~ 2 SPEED AXLE ( WHEN USED ) ►...
Page 540 CHASSIS ELECTRICAL A N D INSTRUMENTS 12-41 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 541 C HASSIS ELECTRICAL A N D INSTRUMENTS 12-42 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 542 tGMTCN CONTROL SWITCH T A C H O M E T E R - R.P.O.1269 (INLINE 6 C Y L .E N G .) IN S T R U M E N T S LOW A IR A L A R M B U Z Z E R R .P .0 .-0 5 0 8 J8 3 Figure...
Page 543 Ef^GK£ ALARM R P 0 .X 5 4 R. P. 0 - 0 6 0 6 H O R N LK3HTNG M ARKER LIGHTS TRL IC C MKR LF? R E L A Y U S E W'TH S E M 1 T R L BR K E C O N T RO L R.RO.^91 R.PO.
Page 544 CHASSIS ELECTRICAL A N D INSTRUMENTS 12-45 CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 545 CH A SSIS ELECTRICAL A N D INSTRUMENTS 12-46 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 546 L E G E N D - O N I T J S I D E i_.H F R A M E - AT k L A R O F C A B E N G H A R N T C A X L E S H I F T MT R C A B E A S M...
Page 547 A M M E T ER Figure 26— Cab, Engine, and Chassis Wiring— H M 80 Sheet 1 of 2...
Page 548 M U LT IP L E . C O N N EC TO R — - I N S T R .P A N E L H A R N .T O DIR .SW . H A R N .- - U N D E R IN S T R .P A N E L A T S T E E R IN G C O L U M N 3 WAY M U L T IP L E CO N N EC TO R...
Page 550 Figure 2 — Radiator Installation (Typical for Figure 1 —Radiator Shell Flexible Mounting H V a n d J V 7 0 M od els) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 551 6. On TM-80 Models, remove nuts, washers Removal (Refer to Fig. 2) 1. Remove radiator shell assembly as de and spring from lower mount. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M AN U A L...
Page 552 Figure 5 — C o m b in a tio n Pressure Relief V a lv e a n d Filler C a p (M od els TM, TG, TJ70 a n d TM 80 ) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH OP M A N U A L...
Page 553 NOT use Glycol Ether (Methoxy Propanol Type) in Toro-Flow II Engines. 10. Drain and flush cooling system every other year, preferably at the begin ning or end of winter operation. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 554 CHASSIS O VERH AU L SECTION ENGINE This manual includes procedures involved in disassem bly and assembly of major components of Chevrolet Series 70 and 80 Heavy Duty Trucks. The Index on this page enables the user to quickly locate any desired section.
Page 556 Refer to “ Specifications” at end of this publication for Figure 1— Sectional V ie w of Rear Axle CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 557 23 Differential Case - Left Lock Washer 48 Washer Cap Screw 24 Nut 49 Nut Figure 2 — Rear Axle Differential an d Carrier Com ponents CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 558 F igure 4 — D ifferen tial B e a rin g C a p a n d A d ju ste r A lig n m e n t M a r k s CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 559 Figure 6 — Removal of Pinion and C a g e Assem bly Figure 8 — Diffe ren tial B e a r in g R e m o v a l w ith Puller CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 560 3. Rinse bearings in clean fluid. W hile holding races to alw ays be cleaned separately fro m other rear axle parts. prevent rotation, blow dry with com pressed air. Do CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 561 REAR AXLE 4-6 not spin bearings while drying. 4. A fter bearings have been inspected as later described, lubricate thorou ghly with regular axle lubricant; then w rap each bearing in clean cloth until ready to use. CLEANING PARTS Im m erse all parts in suitable cleaning fluid and clean thoroughly.
Page 562 90 degrees ap art. If g a p at any point exceeds Figure 12— Checking Alignm ent of Axle Housing CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 563 1. W ith pinion bearings, and adjusting spacers installed in cage, ro tate the cage several revolutions to assure Figure 14— Installing Pinion Inner Bearing CHEVROLET SERIES 70 80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 564 9 Spider Pinion 4 Lock Wire 14 Nut 5 Differential Case - Right 10 Differential Spider T-4331 Figure 16— Differential Assem bly Com ponents CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 565 D ifferential carrier assem bly should be m o u n ted in re W hen using the gauge m ethod, backlash is established pair stand (J-3409) which facilitates repair and ad justm ent CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 566 Figure 18— Worn Tooth Cross Section Figure 2 0 — N o m in a l A sse m b ly D im e n sio n CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 567 8. A fter determ in in g the N O M I N A L A S S E M B L Y D I- Figure 2 7 — C lam p an d Step Plate Installation CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 568 Figure 2 4 — C h e c k in g M icro m e ter on M a s te r G a u g e CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 569 Correct by moving pinion away from backlash is obtained by mov drive gear. ing pinion toward bevel gear. Figure 25— Tooth Contact Chart CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 570 Spider P in io n ........0.02 8"-0.0 32 " 0.06 1"-0.0 63 5" CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 571 B e v e l G ear to C a s e ..........90-100 190-200 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 572 T apered roller bearings are adjusted by selecting a s p a F igu re 1— G e a r Positions in H ig h a n d Low Ratios CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 573 Slidi ng clutch gear, m ou nted over as differential rotates. Oil which is scraped from suppo rt Figure 2 — Sectional V ie w of 2-Speed Rear Axle CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 574 74 Nut 25 Differential Case - Left 50 Fork Seal 75 Cotter Pin T -«8i Figure 3— Rear Axle Differential, Planetary, an d Carrier Com ponents CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 575 Procedure for rem oval of shift unit assem bly is covered in Service portion of this M anu al. Figure 4 — Typical Differential Carrier Assem bly M ounted in Repair Stand CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 576 C -R E M O V A L OF PINION AN D CAGE B— LIFTING DIFFERENTIAL AND A-LEFT BEARING CAP AND PLANETARY ADJUSTER T-4385 Figure 6 — Overhaul Operations CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 577 Figure 8 — R e m o v in g B e a rin g s From P in io n W ith Puller CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 578 Sm all parts such as cap screws, bolts, studs, nuts, etc., should be cleaned thoroughly. Figure 9— Removing Cups From Cage Wi.h Remover CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 579 A — DIFFERENTIAL SIDE GEAR B— DIFFERENTIAL SPIDER, WASHER, C— DIFFERENTIAL BEARING REMOVAL AND WASHER AND GEARS T -4388 Figure 11— Overhaul Operations CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN UA L...
Page 580 A fter axle assem bly has been com pletely disassem bled, Figure 13— Checking Alignm ent of Axle Housing CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 581 REAR AXLE 4-26 17 1819 20 1 Pilot Bearing 8 Pinion Cage 15 Seal Retainer 2 Bevel Pinion 9 Bearing Cup - Outer 16 Prop. Shaft Yoke 3 Bearing Cone - Inner 10 Bearing Cone - Outer 17 Cork Seal 4 Adjusting Spacer 11 Yoke Washer 18 Washer...
Page 582 23 Differential Case - Left 8 Idler Pinion 16 Differential Case - Right T-4383 Figure 17— Com ponent* of Differential an d Planetary Assem bly CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 583 2. Install clutch plate pins and idler pinion pins (7) in Figure 18— Installing Support C ase Bearings Figure 19— C h e c k in g D ifferen tial B e a r in g Pre-Load (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN UA L...
Page 584 0.321” , 0.325” , 0.327” 0.369” , 0.373” , 0.375" R otating T orque (In. L b s.)............. 15-35 15-35 A rbor Press Pressure (T o n s)............9-10 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN U A L...
Page 585 Axle Shaft Flange Stud N ut (1 /2 ” ) ....90-110 90-110 Axle Shaft Flange Stud N ut (5 /8 ” ) ....CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 586 C E D U R E S F O L L O W I N G R E F E R T O F I G U R E 1. 2. R em ove cap screws, stud nuts, an d lock w ashers at- CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 587 (fig. 2), which will facilitate service o p e ra tions. 1. R em ove all differential carrier to axle housing stud CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 588 Figure 5 — R e m o v a l or In stallation o f In p u t S h a ft B e a rin g Retainer CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 589 Figure 9 — R e m o v a l or In stalla tion o f V a c u u m O p e r a te d Sh ift L^ver CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 590 Figure 13— R e m o v a l of O u tp u t S h a ft A sse m b ly Figure 11— Inter-Axle Differential Air Lock-Out Shift Com ponents CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 591 B urnish or ream bushing to size given in “ Specifications.” Figure I S — Pinion C a g » Bearing C u p Removal CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 592 1. Install th ru st w ashers and differential pinions on dif 3. If rem oved press tap ered roller bearing cups into cage CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 593 T ighten cap section for rem oval and installation of air shift cylinder screws only finger tight. assem bly at forw ard axle differential lock cover. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 594 Rotating Torque (In l b s . ) 15-35 Axle Shaft Flange Stud Nut (1 /2 " )....50-60 Axle Shaft Flange Stud Nut (5 /8 " )....90-110 NOMINAL ASSEMBLY DIMENSION....4.125" CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 595 I. A t right side of ad a p te r case, rem ove shift housing ing: cap screws and lock washers, then rem ove housing. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 596 INTER-AXLE DIFFERENTIAL ASSEMBLY BEARING AND OIL SEAL RETAINER DRIVE GEAR INTER-AXLE DIFFERENTIAL COVER AD JUSTIN G SPACER' IDLER P IN IO N ' ADAPTER C A SE' PIN IO N DRIVE GEAR ADJUSTING SPACER ADJUSTING SHIMS DIFFERENTIAL ASSEMBLY PIN IO N GEAR DIFFERENTIAL CARRIER T-1056 Figure 1—...
Page 597 DIFF. CO V ER >N AP R IN G ' O IL SEAL T-4300 ! HIELD - INPU T SHAFT YOKE Figure 1A— Forward Rear Axle Com ponents CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 598 Figure 3 — Differential Carrier A sse m b ly M o u n te d in R e p a ir S ta n d CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 599 Figure 7 — A d a p t e r C a s e A sse m b ly R e m o v e d from Differen tial Carrier CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M AN U A!.
Page 600 Figure 1 1 — Idler G e a r R e m o v a l a n d In stallation CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 601 Puller screws can also be used to Figure 14— Differential Assem bly Rem oval & Installation Figure 15— D ifferen tial A sse m b ly CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 602 1. Press inner pinion bearing o n to drive pinion with wide portion of cone to w ard pinion, until seated against shoulder. U se plates from universal set (J-3493). Figure 16— Differential Bearing Removal CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 603 REAR AXLE 4-48 REMOVING INNER REM OVING INNER BEARING CONE ROLLER BEARING Figure 19— Pinion B e a rin g R e m o v al (Typical) Figure 2 1 — C h e c k in g Fit o f D ifferential B e a r in g C a p 2.
Page 604 Figure 2 3 — D ifferen tial B e a r in g Pre-Load C h e ck CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 605 “ Specifications” rem ove differential assem bly Figure 2 6 — In te r-A xle Differential In stalle d in A d a p te r C a s e CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 606 5. W henever end play of gear does n o t fall within these 2. T a p assem bly into place so th a t rear half of differen- CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 607 SID E G E A R R otating T o rq u e ................5-15 in. lbs. D iam eter at D ifferential C a s e .......... 2.582” -2.587" CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 608 Axle Shaft Flange Stud Nut (1 / 2 ” ) ..........50-60 SID E P IN IO N Axle Shaft Flange Stud Nut (5/8” ) ..........90-110 D iam eter— I.D .................0.877” -0.879” CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN UA L...
Page 610 12. R em ov e nut from piston ro d and rem ove diap h rag m 5. R em ove by-pass tube. an d plate assembly. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 611 11. A ssem ble spacer, large O -ring, block vee, bushing, 28. R em ove snap ring from check valve body and re w asher an d sm all O -ring on push rod. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN UA L...
Page 612 Install front 1. Scribe m a rk s on rear d ia p h rag m housing, clam p band CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN U A L...
Page 613 Bleeder Screw Washer Seal Ring Check Valve Body Check Valve Seat Check Valve Spring Check Valve Snap Ring Hydraulic Cylinder Body Block Vee Control Valve Piston Diaphragm Washer / - s o 40 C o n tro l V alve D ia p h r a g m 41 D ia p h r a g m R e t a in e r C o n tro l V alve D ia p h r a g m R e tu r n S p rin g...
Page 614 15 Hydraulic Cylinder Body 16 Bolt 17 Mounting Bracket 18 Piston /7 ~ 7 T ~ A 19 Block Vee 20 Valve Insert 21 Valve Body 22 Snap Ring 32 Valve Seat 33 Seal Ring 23 Washer 34 Retainer 24 Snap Ring 7 Spacer 35 Snap Ring 25 Gasket...
Page 615: Overhaul
5. E xam in e lock sleeve for cracks or other d a m ag e . R e m ove gear and w orm from slack adjuster body. place if necessary. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN UA L...
Page 616: Standard Brake Cham Bers
Rubber Plug T-2325 Figure 1— Slack Adjusters Figure 2 — S ta n d a r d Brake C h a m b e r (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M A N U A L...
Page 617: S Tan D Ard S To P M Aster B Rake C H A M B E R S
Apply a liberal a m o u n t of rubber ce m en t to boot plate an d d ia p h rag m on the non-pressure plate, w o rk flange an d m ating surface on non -p ressure housing. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN UA L...
Page 618: Dd3 Brake Actuator (Chamber)
Parking and E m e r g e n c y Port Boot 9 Piston G r o m m e t 10 Piston Push R o d Figure 4 — DD3 Brake Actuator (Cham ber) Assem bly CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 619 It m ay be necessary to rem ove the in 10. T urn over non-pressure plate with lock m echanism spection plug to thoroughly clean this passage. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 620: Application V A Lv E S
2. Loosen lock nut and rem ove stop screw. 3. R em ove four retaining screws and pedal bracket. 4. R em ove retainer and plunger from pedal bracket. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 621 Figure 8 — A p p licatio n V a lv e Piston A sse m b ly (M -R ) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN UA L...
Page 622: Relay Valve
4. S ep arate body halves and rem ove spring, diap h rag m 10. D isassem ble inlet and ex h au st valve: an d spring cap. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 623: Moisture Ejector Valve
7 Guide Post 16 Actuator 17 O-Ring 8 Gasket 9 Plunger 18 Gasket 10 Plunger Seat 19 Lowej Body T-1756 Figure 11— Moisture Ejector Voive Com ponents CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 624: Trailer Brake Hand Control V A Lves
C heck exhaust valve seat at small end of piston and inlet valve seat in valve cage for roughness. Slight im- Figure 12— Trailer Brake H and Control Valve-Tilt C ab CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 625 (N .L .G .I. number I with a rust inhibitor ingre dient) to cup bore in piston. Install graduating Figure 15— M e a s u r in g Piston Travel CHEVROLET SERIES 70 80 HEAVY DUTY TRUCK SHOP M AN UA L...
Page 626 (also called T C -2 in sert) in valve body. 10. Remove O -ring from insert assembly. Figure 17— H and Control Valve B-W M odel TC-2 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN UA L...
Page 627 7. Remove graduating spring from body. 7. Install cam follower and cam in cover. 8. Remove piston and block vee assembly from body. 8. Install graudating spring in body. Remove block vee from piston. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN UA L...
Page 628: Limiting Quick Release Valve
2. Push valve carrier with inlet and ex haust valve assem bly out of valve body. R em ove O -rings from grooves in valve body and discard. Figure 20— Tw o-W ay Control Valve CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 629 3. Install k n o b on valve piston. T ighten finger tight. sm all end of plunger, an d install plunger an d spring in 4. A fter installing valve in vehicle, test valve for proper top of body. operation. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M ANUAL...
Page 630: Trailer Emergency Air Supply Control V A Lv Es
9 Piston O-Ring______ Figure 2 2 — Air Supply Control V alv e (B-W ) Figure 2 3 — Air Supply Control V alve (M -R ) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 631: Tractor Protection (Breakaw Ay) Valves
21 Ball Valve Retainer Diaphragm Washer -2794 O-ring T-2796 Figure 24— Tractor Protection V alve (B-W ) Figure 25— Tractor Protection V alve (M -R ) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 632 3. R em ove ex haust check valve end cap, spring, and ball. Figure 2 7 — In version V a lv e A sse m b ly CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN UA L...
Page 633: Inversio N Valve
8. Install sealing ring on cap nut, install ca p nut with valve cap and discard. sealing ring and tighten securely. 5. R em ove valve stop, valve spring and valve. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 634: M-R Air Supply Valve
Place valve cap in position on valve body and secure 1. Place valve spring in valve body. with two screws. 2. Install O -ring on plunger. Install inlet an d exhaust CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN UA L...
Page 635: B-W Air Supply Valve (M Odel P P - 2 )
Figure 32— Air Supply Control Valve (M -R) Figure 3 3 — A ir S u p p ly Control V a lv e ( B - W PP-1 a n d PP-3) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 636: Safety Valve
ASSEMBLY (Fig. 35) 3. C h eck spring for rust and cracked or w eakened coils. R eplace if necessary. I. Install adjusting screw part way into spring cage. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN U A L...
Page 637 9 Guide 14 Contact Strip 4 Disc 10 Shuttle Valve 15 Piston 5 Identification Washer 11 Gasket 16 O-ring Diaphragm 6 Spring T-4342 Figure 36— Check Valves CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 638 7. Place spring in center of piston and co m press it with the stop light switch cover. A lign cover, hold in place, and fasten with tw o screws an d lock w ashers. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 639 U n lo ad e r line or cavity to governor restricted. C o m p resso r not getting proper lubrication. U n lo ad e r m echan ism binding or stuck. Excessive wear. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 640 19 Bearing Cap Gasket (Front) Discharge Valve Spring _ 4 8 2 10 Piston Pin Lock 20 Crankshaft Bearing (Front) Cylinder Head Figure 1— M idland-Ross Air Compressor (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 641 2. R em ove two stud nuts which attach governor m o u n t O n air-cooled m odels, rem ove air strainer from inlet CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 642 Lift cylin der block off cran kcase an d pistons. R em ove gasket be Figure 3 — Cross Section of Cylinder Head CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 643 INLET VALVE GUARD A N D VALVE REMOVED Figure 5— Inlet V a lv e a n d G u a r d R e m o v a l CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 644 A fter lapping, thorou ghly clean are available in 0.010 inches, 0.020 inches and lapping c o m p o u n d from valves and seats. 0.030 inches oversize. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 645 3. E xam ine ball bearing for worn or d a m a g e d balls; ro- inserts if clearances are excessive. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN UA L...
Page 646 5 Housing Lock Nut 8 Valve Assembly 11 End Cap 6 Housing O-ring 9 Governor Body 3 Spring T - 4 3 9 1 Figure 10— Governor Com ponents CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 647 F igure 11— In sta llin g B e a rin g A sse m b ly U s in g A rb o r Press Tool CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 648 Oil Ring Oil Ring Expander Piston Pin Lock Wire Piston Pin Piston Compression Ring (2nd) 47 Compression Ring (1st) 48 Washer T-4130 Figure 12— Air Compressor Com ponents CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 649 12 to 17 foot-pounds torque. Figure 1 5 — Piston a n d C o n n e c tin g Rod A sse m b ly CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 650 M ak e Efficiency test is m ade by running co m presso r for one- sure th a t tube connections are tight. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN UA L...
Page 651 Groove Clearance Top Com pression Ring 0 .0 01 "-0 .0 0 3 ".. 0.001"-0.003" Second Com pression Ring 0.001"-0.003" . .. 0.001"-0.003" Oil Ring 0.0010"-0.0035" 0.0010"-0.0035" CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M A N U A L...
Page 652 ............85 p s i............85 psi CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN U A L...
Page 653 C o m p resso r not getting proper lubrication. U n lo ad e r line or cavity to governor restricted. Excessive wear. U n loader m echanism binding or stuck. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN U A L...
Page 654 10 Crankshaft Bearing 35 Unloader Spring Seat 23 Piston Pin Lockwire 11 Oil Seal Ring 24 Piston 12 Thrust Washer T-1833 Figure 1— Bendix-W estinghouse Air Compressor (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 655 U p stro k e of one piston ex Figure 4 — U n lo a d in g Com pressor CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 656 TO CYLINDER HEAD Piston 1. Loosen two cap screws which attach the governor bracket to air co m presso r head. Figure 6 — Unloader Assembly Com ponents CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 657 R em ove connecting rod bearing caps an d bearing inserts. Push pistons with connecting rods attach ed out top of cylinder block. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN U A L...
Page 658 R em ove all sedim ent from T horoug hly clean oil passages throug h crankshaft, co n sum p in b o tto m of cover. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN U A L...
Page 659 W ipe dow n the cylin- C heck fit of piston rings in ring grooves, and CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M A N U A L...
Page 660 Figure 13— Piston Ring Arrangement and Clearances (12 cu. ft.) Figure 12— Piston Ring Arrangem ent an d Clearances (7 1/4 cu. ft.) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN UA L...
Page 661 4. Install rear end cover and bearing assem bly against BELT-DRIVEN TYPE the crankcase. 1. Install ball bearing on front of cran ksh aft. Press bear- 5. Install cap screws and w ashers attaching end cover to CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN UA L...
Page 662 57 Insert Bearing 63 Discharge Valve Seat 52 Main Insert Bearing 64 Gasket 58 Connecting Rod 69 Tube Assembly t - a i Figure 15— Air Compressor Com ponents CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 663 1. Position connecting rod in piston and press piston pin block. Refer to Figure 19 for an example of into piston with lock wire holes in pin aligned with staggered ring gaps. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 664 PISTO N C O N N E C T IN G INSERT BEA RIN G T-4168 RO D CAP Figure 19— Piston an d Connecting Rod Assem bly CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN U A L...
Page 665 4. Install new gasket and replace air inlet elbow. 2. T he other type governor is m o u n ted on the com pres- Figure 22— Installing Unloader Com ponents CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 666 T h e piston an d inlet ex h au st valve move up governor body. when reservoir pressure reaches cu t-o u t setting of the gov 5. R em ove the piston assem bly from governor body. It CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN U A L...
Page 667 18 P iston G r o m m e t 19 G o v e rn o r Body 9398 Figure 26— Type " D - 2 " Governor Com ponents CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN U A L...
Page 668 3. Install air strainer unit with a new gasket to c o m p res the dash air g a ig e is registering accurately. U se an a c cu sor by using two cap screws and washers. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M AN U A L...
Page 669 .0 3 0 O v e rs iz e ( G ) * 2 .0 9 2 0 " - 2 .0 9 2 5 " 2 .0 9 2 0 " - 2 .0 9 2 5 " CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN U A L...
Page 670 Narrow R in g ............. . . 0.002"-0.004" 0 .0 0 2 " - 0 .0 0 4 " CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 671 * C o lo r Id e n tific a tio n M a rk s R -R e d , Y - Y e llo w . B - B lu e , G -G reen CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 672 C ore holes, bearing bores, and other openings are closed with plugs or plates. Figure 1— Typical V -6 , M o d e l 4 7 8 M E n gin e CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 673 C r a n k s h a f t end-thru st is taken by a special aft directions. Seal at crankshaft rear bearings is packing flanged bearing located at No. 3 journa l. Adjace nt cheeks type. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 674 Pistons are p erm anen t-m old alu m in u m castings with Cylinder heads are interchangeable between cylinder banks. cast-in steel expansion control band. Piston pins are re CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 675 Figure 5 — R e m o v in g Piston a n d C o n n e c tin g Rod w ith G u id e Set CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 676 Figure 7 — T im in g Idler G e a r S h a ft In stallation ( 4 0 1 M a n d 4 7 8 M Engines) 1. Cylinder Block 7. Full Pressure Oil 3. Oil Hole 5. Crankshaft Gear 2. Idler Gear Shaft 4. Bolt 6. Lockwasher Gallery CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 677 (fig. 7) which is tight fit in counterbore in block. 2. Pull cam sh aft forward to remove from cylinder block. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 678 Figure 10— Tool Set (J -2 1 0 9 9 -1 5 ) for R e p lac in g C a m s h a f t B e a rin gs CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 679 Figure 11 — Rem oving C am shaft No. 4 (Rear) Bearing CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 680 Figure 1 3 — C a m s h a f t B e a rin g In stallation CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 681 1 bearing bore. With driving button on front end of a tac hom e ter drive unit. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 682 EN G IN E 6-11 _______________________________TP 3869 Figure 15— M e a s u r in g B e a rin g Thickness Figure 1 8 — C h e c k in g Pilot H ole Concentricity a t F lyw h eel H o u s in g CRA N KSH A FT A N D B E A R IN G S C L E A N IN G 1.
Page 683 E N G IN E 6-12 center (No. 3) ma in bearing for evidence of wear where they contact the sides of the bearing inserts. M easure FLYWHEEL H O U S IN G A N D FLYWHEEL bearing journa ls with m icrom eter to determine if they are out-of-round an to check the extent of wear.
Page 684 Figure 2 0 — Flyw h eel M a c h in in g Instructions (w ith 14-In. Clutch) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 685 E N G IN E 6-14 cessive wear, new pistons should be installed. M easure 3. Bearings piston pin bores in piston bosses, and c o m pare with d i a m Carefully inspect connecting rod be aring halves for eter of pins.
Page 686 Clean cylinder walls with Figure 2 3 — R e m o v in g G e a r from C a m s h a ft CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 687 sembled to cylinder block. Figure 2 5 — Rem oving C am shaft Gear with Puller CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 688 Figure 26. C r a n k s h a f t should be posi If necessary to replace gear, follow the pr ocedure given tioned so key is at 12 o'clock position when assembling CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 689 \ FEELER GAUGE ■ > PUMP BODY CHECKING INNER-TO-OUTER ROTOR CLEARANCE MEASURING ROTOR END CLEARANCE Figure 29— Checking for W ear at Engine Oil Pump Rotors CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 690 (7) in body. 3. Install cover (8) on p um p and retain with four cover beyond inner face of cover. CHEVROLET SERIES 70-80 HEAVY D U TY TRUCK SH O P M A N U A L...
Page 691 4. Place the outer rotor (13) in body (3) and insert inner Figure 3 2 — Use of Special Tool for R e m o v in g E x h a u st V a lv e S e a t Ring CHEVROLET SERIES 70 80...
Page 692 EN G IN E 6-21 1. Install pressure relief valve parts in p u m p body (3) in 3. Check valves for burned or pitted faces an d for wear order shown in Figure 29. Tighten spring cap firmly. or corrosion at valve stems.
Page 693 60 degree stone to grind from bottom of seat. Refer to Figure 31 for proper width for valve seats. d. Test valve for perfect contact with seat in cylinder CHEVROLET SF R 'E S 70-80 u F A Vv r-urv S 'J...
Page 694 (2). surface on p u m p body (fig. 35). 3. Drive seal (3) out of p um p body. If seal seat (4) in CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 695 EN G IN E 6-24 6. While supporting rear end of p um p shaft, press pulley hub on front end of shaft to dimensions shown in Fig ure 36. Note tha t the p u m p extended side of hub (1) is toward bearing.
Page 696 EN G IN E 6-25 7. Dip the two bearing cap side seals in Diesel fuel oil, seating of bearing cap if ends should extend then insert one seal into groove at each side of rear betw een cap a n d cylinder block. bearing cap.
Page 697 , using foot-pounds. gasket between ca p and block. Use flat steel wa sh er CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 698 Figure 4 3 — Se rial N u m b e r Plates on H y w h e e l H o u s in g a n d A d a p te r must be taken to rem edy the condition. Plate CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 699 7 Oil Control Ring (One-Piece Flexible) 8 Top Groove Insert (Integral with Piston) T-2692 Figure 4 6 — Piston Ring Arrangem ent for 4 01M Engines CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 700 Q U I C K , F I R M , P U S H . edge to w ard botto m of piston. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 701 Figure 5 1 — In sta llin g C y lin d e r H e a d A sse m b ly CHEVROLET SERIES 70-80 HEAVV DUTY TRUCK SH O P M A N U A L...
Page 702 Figure 5 3 — Valve Timing D iagram for 4 0 1 M an d 4 7 8 M Engines CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 703 After the unit is installed in vehicle, the sam e p r o stalled, the unit should be given a preliminary run-in on a cedures should be applied. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 704 Rocker Arm Shafts 12. Oil Pump 6. Rocker Arm Shaft Rear Bracket 13. Piston Pin Splash Lubricated 7. Oil From Camshaft Rear Bearing 14. Idler Gear Shaft CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 705 Crankshaft Supported at End Journals (Max.) . 0.0030” Crankshaft Main Bearing Bore (Less Allowable Runout at Flywheel Mounting Inserts) All Bores....... 3.325"-3.326" Flange (at 2" R ) ........0.001” T.I.R. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 706 4.8711"-4.8714" 4 7 8 M ........... 0.026”-0.036" 4.8714"-4.8717" 2nd Ring 4.8717"-4.8720" 4 0 1 M ........... 0.015”-0.025" 4.8720”-4.8723" 4 7 8 M ........... 0.017”-0.027” 4.8740"-4.8743" CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 707 Intake O p e n s ..........27° BUDC Fuel Pump Eccentric Bo lt........50-60* Intake Closes..........61° ALD C Oil Filter Housing to Cyl. Block B olts....26-36 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 708 (1) At 16” above the outlet when pump is operated at 1. If rocker arm has been removed, place retainer and 1800 R.P.M . CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 709 3. Remove fuel valve needle, seat, and gasket (13) from avoid loss of pump check ball (12, fig. 3) when body (14). handling main body assembly. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 710 (19), an d governor d ia p h r a g m spring 4. R em ov e idle m ix ture screws and springs (11 and 10) (18) from housing (17.) from throttle body. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 711 Lock W asher Body Screw spection instructions applying to parts included in kit m ay 4. Spring Anchor 8. Link be disregarded. 9. Housing CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 712 5. Throttle Driver 10. Mixture Screw Springs Screw and Lock C AUTIO N : Do not rem ove throttle shaft bear- 11. Idle Mixture Screws Washer CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 713 Figure 7. Hold plates closed and tighten throttle plate screws securely. Key num bers in text refer to Figure 2. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 714 (viewed from lever end of shaft), then tighten screw to j u s t m e n t s ” in Service Section 6M of this manual. lock lever to bushing. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 716 G R O U N D E D B R U SH H O L D E R T - 4 3 4 6 Figure 1— Light-Duty Type Starting Motor With Stam ped End Frame (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 717 SOLENOID ASSEMBLY Figure 2 — Light Duty Type Starting Motor (M odel 1107586) (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 718 FIELD COIL J ARMATURE / " O ” RING HEAVY-DUTY COMMUTATOR POLE SHOE SHAFT SEAL BRONZE BUSHING CLUTCH Figure 4 — Heavy-Duty Type Starting Motor (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 719 (fig. fective and must be replaced. If any coil is replaced, CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 720 E N G IN E ELECTRICAL 6Y-5 Figure 7 — C h e c k in g A rm a tu re For G ro u n d s T w o brush holders are insulated from the end frame and two are grounded .
Page 721 SPRING STOP W ASHER LOCK WIRE LOCK WIRE PINION, SHELL A N D B U SH IN G ASSEMBLY Figure 9 — Intermediate-Duty Sp rag Clutch CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 722 Figu re 12— Circuit For C h e c k in g Pinion C le aran ce Figure 11— Forcing Retainer Over Sn ap Ring CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 723 Remove washer. Figure 14— M e a s u r in g Pinion C le a ra n ce (H e a v y Duty) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 724 6. Observe a m m e t e r , voltm eter and tac hometer, and IMPORTANT: Make sure the motor field coil co m pare readings with specifications. connector is disconnected during this test. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 725 5600 ■ M axim um RPM 8750 10,400 7600 ± 'l h i . ( *) Includes Solenoid. (a) Pinion Clearances 0.010"-0.140". (b) Pinion Clearances CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 726 “ C o n d e n se r .” A defective condenser will cause distributor is not to be installed at this time. excessive pitting of contact points. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 727 Attaching Screws 27. Breaker Plate Attaching 5. Weight Cover Attaching 10. Cam Assy. 16. Cushion Assy. 22. Vacuum Control Assy. Screws 2 8 . Tension Spring CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 728 HEAT SIN K ROTOR ASSEMBLY DIODES Figu re 1— End V ie w an d Cross Section of 42 an d 61-Am p. Generator (Typical) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 729 ? s i Figure 3 — Replacing Pulley Nut (Typical) Figure 4 — Stator Leads a t Junction Stu d s CHEVROLET SERIES 70-80 HEAVV DUTY TRUCK S H O P M A N U A L...
Page 730 Figure 7 — Te stin g D io de s a n d C a p a c ito r CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 731 Check can be m a d e with 12-volt test la m p or a I I - 1/2 end frame. Key num bers in text refer to figure 8. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 732 F ig u re 1 0 — H e a t S in k a n d R e late d P arts D isa s s e m b le d CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 733 10 and 12. T o remove studs, support heat sink at flat service replacement. Stud and insulator are shown in Fig- side and press studs out of insulators. W ith pliers, remove CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 734 F ig u re 1 6 — In sta llin g D io d e s in H e a t S in k F ig u r e 1 7 — Rotor a n d S lip R in g A s s e m b ly CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 735 5000 Rated Hot Output........*If generator output is checked without a regulator., the output should be 5 to 10% higher than the value given. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 736 After inspection and bench test of F ig u re 1— 6 2 - A m p . G e n e ra t o r (T yp ica l) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 737 (fig. 5). Touch the leads from lamp or ohm m eter to stator windings described following: CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 738 F ig u re 6 — C h e c k in g for G r o u n d e d or O p e n C ircuit in Sta to r CHEVROLET SERIES 70-80 HEAVY DUTv TRUCK SH O P M A N U A L...
Page 739 F ig u re 7 — T e stin g D iod e s CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 740 5. Drive End Frame 12. End Frame Attaching Bearing Bolt I. C ut or unsolder stator leads and diode connecting 6. Shield 13. Special Nut CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 741 Visually inspect the diodes for failure. color markings, and note that the heat sink CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 742 1. Slip Ring End Frame 4. Capacitor 6. Bearing Assembly 2. Bearing Lubricant 5. Lead (To Relay 7. Bushing 3. Rotor Terminal) 8. Bearing Seal Ring CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 743 B A T T E R Y C O N N E C T IO N S WILL D A M A G E G E N ERA TO R. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 744 Rated Hot Output (A m ps.)..........*If generator output is checked without a regulator, the output should be 5 to 10% higher than the value given. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 746 All parts, except those being actually worked on, should be kept covered with clean paper. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 747 17. Spring 36. Countershaft Front Bearing 53. Poppet Ball 18. Mainshaft Retainer 54. Spring 19. Mainshaft Rear Bearing Retainer 37. Countershaft Front Bearing 55. Gearshift Lever CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 748 TRANSMISSION AND CLUTCH 7-3 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 749 1. Clutch Housing 2. Snap Ring (Selective) 3. Clutch Gear 4. Synchronizer Outer Stop Ring (Front) 5. Synchronizer Inner Ring and Pin Assembly (Front) 6. 4th and 5th Speed Sliding Clutch 7. Synchronizer Inner Ring and Pin Assembly (Rear) 8. Synchronizer Outer Stop Ring (Rear) 9.
Page 750 35. 4th and 5th Speed Shift Rail 66. Retaining Washer Bolt 36. 2nd and 3rd Speed Shift Rail 67. Thrust Washer 37. 2nd and 3rd Speed Shift Fork 68. Countershaft Drive Gear 38. Reverse Shift Fork 69. Countershaft 4th Speed Gear 39.
Page 751 F ig u re 5 — M a i n D riv e G e a r R e m o v e d CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 752 4. Idler Gear Shaft 7. Transmission Case 2. Reverse Idler Gear and Bushing 5. Lock Screw 8. Countershaft 3. Reverse Shift Fork 6. Lock 9. Removing Tool CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 753 Accomplish the following procedures: F ig u re 9 — R e m o v in g S h ift Fork Lock Pin CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 754 2. Remove all portions of old gaskets from parts, using Same number of shims should be installed a stiff brush or scraper. when transmission is reassembled. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 755 Figu re 1 2 — R e m o v in g C o u n t e r s h a ft R e a r are not recomm ended, replace dam aged parts. B e a r in g fro m R e ta in e r CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 756 Key num bers in text refer to figure 13 unless otherwise tain that synchronizer parts are square and that the specified. gauges are sufficiently close to the center of the shaft CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 757 F igu re 1 4 — 4 th S p e e d G e a r S h im s a n d C lu tc h G e a r In stalled CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 758 (21). Use sealing cement on plugs to idler shaft so lock notch in shaft faces down toward prevent lubricant leakage. lock screw tapped hole in transmission case. CHEVROLET SERIES 70-80 HErAV'/ DUTY TRUCK SH O P M A N U A L...
Page 759 (65) in bore of transmission case (77). 4. Install drive gear bearing retainer (61) using two new 2. Position thrust washer (67) on front end of counter- CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 760 5th Speed..........1.00 to 1 1.00 to 1 Dia. at Front Bearing Surface......1.3775” - 1.3780” Reverse.............7.22 to 1 6.13 to 1 Dia. at Rear Bearing Surface.......1.7485” - 1.7500” CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 761 Length Under 5 lb. L oad............. 0.4375” Clutch Housing Cover Bolts........8-10 ft.-lbs. Solid Length................0.3125” Brake Locating Bracket B olt........65-75 ft.-lbs. Brake Anchor Bar Bolt..........65-75 ft.-lbs. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 762 Dis splines will not be damaged. card gasket. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 763 6. Remove 2nd gear retainer ring, 2nd gear and locating 4. Remove 4th and 5th shift fork roll pin, shaft rod and washer (fig. 15N). fork. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 764 Clean interior and exterior of housings, bearing caps, F ig u re 2 N — C o v e r E x p lo d e CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 765 F ig u re 3 N — T ra n sm issio n A s s e m b ly — E x p lo d e d V i e w CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 766 F ig u re 5 N — R e m o v in g R e a r B e a r in g C a p CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 767 F ig u re 9 N — R e m o v in g R e v e rse Id ler S h a ft CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 768 F ig u re 1 3 N — R e m o v in g 4 th a n d 5 th S h ift H u b S le e v e R e ta in e r R in g CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 769 F igu re 1 7 N — R e m o v in g 2 n d a n d 3 r d S hift Fork Roll Pin CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 770 F ig u re 2 1 N — In s ta llin g C o u n t e r s h a ft Front B e a r in g CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 771 2 5 N — P o sitio n in g R e a r B e a r in g a n d O il S lin g e r CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 772 F ig u re 2 7 N — Position R eve rse Id le T h ru st W a s h e r s F ig u re 2 9 N — M a i n D riv e G e a r In stalled CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 773 F igu re 3 1 N — P o s itio n in g Lock B a lls a n d S p r in g s in S u p p o r t H o u s in g CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 774 40. Welch Plug 20, Shift Fork Lock Pin ^1. Control Top Screw and 21 . 2nd and 3rd Fork Assembly-lnc. Items 18 and 19 Lock Washer CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 775 (38), pull shaft out of transmission case and rev 2. Remove power take-off covers and gaskets. Discard erse idler gear (35) (fig. 4P). gaskets. 3. Remove reverse idler gear (35), bearings (36), and CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 776 49. 2nd Speed Gear Retainer Washer 16. Poppet Spring 33. Reverse Idler Gear 50. 2nd Speed Gear Snap Ring 17. Poppet Ball 34. Reverse Idler Gear Bearings CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 777 TRANSMISSION AND CLUTCH 7-31 Figure 2P— Transmission w,Shift Bar Rerroved 1. Main Drive Gear 5. Countershaft 4th Speed Gear 9. Mainshaft 1st and Reverse Gear 2. Countershaft Drive Gear 6. Mainshaft 3rd Speed Gear 10. Mainshaft 3. 4th and 5th Synchronizer Assy. 7.
Page 778 F igu re 5 P — R e m o v in g C o u n t e r s h a ft R e a r B e a r in g CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 779 11. Rem ove lock screw (4) from 1st and reverse rocker latch plunger and spring from well in 1st and reverse lug (11), and from 1st and reverse shift lug (3). shift lug (fig. 10P). CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 780 F ig u re 1 0 P — 1st a n d R e v e rse S h ift L u g a n d Latch P lu n g e r CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 781 F ig u re I I P — T ra n sm is sio n E x p lo d e d V i e w CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 782 R otate each bearing slowly while exam ining balls or 2. Remove jam nut or snap ring (78) retaining bearing rollers for roughness, dam age, or excessive wear. assembly (77) on drive gear (76). CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 783 S upport front inner race of bearing and press gear into bearing tight against front face of gear. seal goes in toward transmission case. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 784 TRANSMISSION AND CLUTCH 7-38 3. Install bearing retainer nut or snap ring (78). b. Holding snap ring (17) parallel to retaining 4. Assemble the pilot bearing in the main drive gear as washer (18), slip snap ring into snap ring groove follows: in mainshaft (43).
Page 785 Align lock screw hole in shift fork with hole in Key num bers in text refer to Figure 7P. shift rod, then install lock screw (13), tighten CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 786 W a s h e r F igu re 1 4 P — A d ju s tin g Latch P lu n g e r CHEVROLET SERIES 70 80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 787 Number Rollers................12 Inside Diam............1.9680” - 1.9685" Make and N um ber..........Hyatt SRA-5206 W idth................9005” - .9055” Inside Diam. of C age............... 1.635” CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 788 Number of Clutch T eeth............Backlash with M ate ..........0.006” - 0.010” REVERSE IDLER GEAR Hub W idth..............1.937” -1.947” Diam. of B ore............1.750” - 1.751" CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 789 W idth................. 1.235” - 1.238- TORQUE WRENCH SPECIFICATIONS Location Foot-Pounds Selector Finger to Shifter Shaft Screw........25 Companion Flange or Yoke N u t ........400-450 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 790 F ig u re 1 — T ra n sm issio n S hift P a tte rn s (C la r k M o d e l 3 8 5 V , 3 8 7 V ) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 791 (25 and drum , if used) from rear end of m ainshaft (22). 30) and gaskets. Discard gaskets (24 and 33). CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 792 (23) clears transmission case. 1 1. Using a suitable puller, remove m ainshaft rear bear- 1. Push countershaft (34) toward rear to move counter- CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 793 F ig u re 6 — R e m o v in g C o u n t e r s h a ft R e a r B e a r in g CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 794 (16). Key n um bers in text refer to Figure 9 or 10. 8. Remove lock screw (4) securing 1st and reverse shift CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 795 F ig u re 1 2 — 1st a n d R e v e rse S h ift L ug a n d Latch P lu n g e r In stalle d (Late Type) Type) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 796 (4). 2. Inspect all parts for discoloration or warpage due to 4. Remove two remaining W oodruff keys (89) from heat. countershaft (52). CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 797 TRANSMISSION AND CLUTCH 7-51 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 798 Install drive gear bearing cap (80) over drive gear (76) ■ — CNfO’ ^-iO'dr^cd O ' O C N M and bearing (77) and secure in place with bolt and lock washer assemblies. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 799 F ig u re 1 5 — S e le ctin g 4 th S p e e d G e a r V a r ia b le T h ic kn e ss R e ta in e r W a s h ing sleeve (49). CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M AN UAL...
Page 800 (28) on shift rod with hub tow ard rear, and stall snap ring (9) into groove of m a in sh aft (43). install interlock cross pin (22) in hole in shift rod. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M AN UA L...
Page 801 “N eutral” at the same time. R od s should not shift into more than one speed at a time. Figure 16— A djusting Latch Plunger CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 802 25-31 ring on bearing (5) contacts transmission case. It may foot-pounds torque. be necessary to use a suitable sleeve and hammer to CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 803 Backlash with M ate........ 0.005”-0.010” Number Balls and Size........(12) 11/16" Diameter at Gear E n d ......4.069"-4.079" Make and N um ber......Corporation #954114 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 804 W id t h ..............1.250" Notches (Outer) Number .......... SPRINGS Notch (Inner) N u m b e r ..........1st and Reverse Latch Plunger Spring CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 805 Inside Diam eter........2.377”-2.387" Shift Lever Pivot Bolt N u t s ........25-31 Outside Diam eter..........3-3/16” Companion Flange N u t ..........Thickness..........0.142”-0.144” CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 806 F ig u re 1 — C la rk 4 0 0 S e rie s T ra n sm issio n S h ift D ia g r a m CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 807 TRANSMISSION AND CLUTCH 7-61 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 808 SHIFT B A R H O U S IN G R E M O V A L specified. T he following procedures cover com plete overhaul of 1. R em ove control top oil baffle (3, fig. 12) if used. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 809 3. R em ove bolts an d lock w ashers; then rem ove counter- a. U sing a plastic h a m m e r, tap on th read ed or rear CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 810 W ra p a piece of strong rope aro u n d the assem bly CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 811 21. Interlock Hole Welch Plug 13. 4th and 5th Shift Rod 6. Lock Screws 7. 4th and 5th Shift Fork 14. 1st and Reverse Shift Rod CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 812 F ig u re 1 3 — R e m o v in g M a in s h a f t Pilot B e a r in g Figure 15— R e m o ving 4th Speed G e a r B u sh in g Sleeve CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 813 F ig u re 1 8 — R e m o v in g C o u n t e r s h a ft D riv e G e a r CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 814 71. Rotor Drive Pin 28. Bearing C ap Attaching Bolt Bushing Assembly 72. Bushing Sleeve Pin L e g e n d for Fig. 21 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 815 Fig. 2 1 — C la r k 4 0 1 T ra n sm is sio n C o m p o n e n t s CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 816 “ soft-jaw s,” th a t tool should be used. S ubst- sion. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A !
Page 817 Figure 2 3 — Installing M a in sh a ft 2 n d Spe e d G e a r V a ria b le Thickness Re a. Before 2nd speed gear (56) is installed on bushing tainer W ashe r CHEVROLET SERIES 70-80 H E AV Y DUTY TRUCK SH O P M A N U A L...
Page 818 (fig. 27). F ig u re 2 5 — A d ju s tin g Latch P lu n g e r CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 819 5. 4th and 5th Shift Fork 2. 2nd and 3rd Shift Fork 9. Shift Rod Supports 6. 1 st and Reverse Shift Rod 3. 2nd and 3rd Shift Rod CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 820 (39). 4. Install reverse idler shaft lock plate (39) on idler shaft will allow shift rod to pass through center rod CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 821 11. Lock transm ission gears into two speeds at the sam e with four bolts and lock w ashers. T ighten bolts se tim e and tighten co u n tersh aft rear bearing retaining curely. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 822 D ia m e te r a t Spline E n d ......1.495” -1 .4 9 9 " Outside Diam eter......3.9364”^3.9370" N u m b er of S p lin es ..............10 Inside Diameter........ 1.7712” -1.7717” CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 823 Diameter of B o r e ........1.875"-1.876" Inside Diam eter........3.034”-3.044" Outside Diameter—Rear G e a r ....4.190”-4.200" Outside Diam eter..........3-13/16” Outside Diameter—Front G e a r ....4.476”-4.486" CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 824 Outside D ia m e te r ........... 3.142"-3.152" Shift Lever Pivot Bolt Nut ........25-31 T h ic k n e s s ............0.166"-0.168” Companion Flange Nut..........CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 825 If rem ote controls are used, a careful check of the trouble in the transm ission; while, actually the rem ote and connecting linkage to transm ission and CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 826 M echanics should try to locate and eliminate noise by CHEVROLET SERIES 70-80 H E AV Y DUTY TRUCK SH O P M A N U A L...
Page 827 10. D a m ag e d synchronizer such as b roken pop p et springs, him self th a t the rem o te units are satisfactory and that CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 828 7. B locker pins loose, broken, or turned over. All bearings are subject to fatigue an d m ust be replaced CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 829 F ig u re 1— S p ic e r 5 0 0 0 S e rie s 5 - S p e e d T ra n sm issio n CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 830 (U s e d o n Tilt C a b M o d e ls) Figure 3 — R em o ving Reverse Idler G e a r Shaft CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 831 (4 ) to fall into the bctto m o f the C a b Models) tran sm issio n case. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 832 11 4th and 5th Shift Rod 17-Set Screw T-4116 F ig u re 6 — S h ifte r H o u s in g CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 833 (8) out of control tow er and rem ove gearshift move lock wire and shift finger screw (21) from shift fin lever (22). ger (4). CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 834 6. Drive plug free of housing an d tap fork until 1st and 5. R em ove the rem aining co u n tersh aft gear key (9). CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 835 1. R eplace all gaskets, oil seals, lock wire, cotter pins should be replaced. and sn ap rings. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 836 O P E N I N G S in groove on m ain drive gear. Install large snap ring on m ain drive gear bearing. Figure 11— Assembled Shifter Housing CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 837 TRANSMISSION AND CLUTCH 7-91 8. L ock sleeve and clutch gear in place with snap ring of rod into upper expansion plug opening. Position 4th (5). Avoid distorting snap ring during assem bly. S eat snap and 5th shift fork (12) on rod as shown in figure 11. T ap ring in groove of m ainshaft.
Page 838 N O T E : T a p b e a rin g until s n a p rin g is flush w ith against bearing. case. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 839 4. Install rem o te control assem bly- to- shifter housing cotter pin. attaching p a n s . T ighten ca p screws firmly. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 840 L e n gth ..........6 .7 4 0 "-6 . 7 6 0 " Pilot Bearing Su rfa ce .......2 .0 6 2 6 -2.0631 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 841 N u m b e r Teeth (O u te r)..........2 9 H ub W id th ..........1 .4 9 8 "-1 .5 0 2 " CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 842 Clutch H o u sin g Retaining C a p S c re w s ..6 0 -8 0 Poppet or Interlock Ball CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 843 R efer to “ Specifications” at end of this section for fits Using arb o r press or suitable bearing puller, rem ove and tolerances. bearing assem bly (35) from drive gear. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 844 19 Gasket 1 Direct and Overdrive Shift 9 Low Speed Clutch Gear 20 Mainshaft Low Speed Gear Fork 10 Bearing Snap Ring 2 Set Screw 11 Mainshaft Rear Bearing 21 Bearing Cup 22 Bearing Cone 3 Lock Wire 12 Rear Bearing Cap 23 Countershaft Rear Bearing 4 Shift Collar 13 Speedometer Drive Gear...
Page 845 2. A ssem ble shift fork (7) on rod an d retain with set screw' and lock wire. tershaft. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S'-IOP M A N U A L...
Page 846 (35) into case and secure with snap ring (34). assem ble hand brake m echan ism a t rear of tra n s m is See Figure 4. sion. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 847 Countershaft ........0.006"-0.011" Drive Gear Nut ......... 400-450 ft-lbs. Drive Gear and Mainshaft Mainshaft Nut ........400-450 ft-lbs. O.D. Gear to Countershaft Gear..0.006"-0.009” CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 848 2. R em ove pop pet screw from each side of cover an d ja r springs, balls, an d retainer out throug h pop pet screw Key num bers in text refer to Figure 1. holes. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 849 16. Direct and Overdrive Shift 54. Bearing Cone 36. Rear Bearing C ap Adjusting Shims Fork 55. Seal Cap (0.003, 0.010 & 0.030) 17. Mainshaft Overdrive Gear CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 850 (50) an d Install inner bearing (54) on m ain drive CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 851 (14 and 22). Install b rea th er assem bly 2. L ow er the co untershaft and gear assem bly into case in transm ission cover. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 852 1.393", 1.395” - Select as required. Sliding C lutches to Clutch G e a r s ..... 0.004”-0.007" C ountershaft R ear Bearing Cap Shim T hickness 0.003", 0.010", 0.030” CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 853 6. 3-4 Shifter Fork 10. Shift Rod Seals 3. Poppet Springs 7. 1-2 Shifter Fork 11. Shift Rod Interlock 4. Poppet Balls 8. 3-4 Shift Rod CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 854 TRANSMISSION AND CLUTCH 7-108 5. W ith long hub tow ard the front, assem ble lst-2nd 6. R em ove old gaskets or sealing m aterials from m a shift fork (7) to lst-2nd speed clutch collar (7), Figure chined surfaces and clean case cover.
Page 855 .0015" to .003" is built into new parts, i t 14). S e p a ra te bearing caps from gaskets, shim s and presents a field assembly problem. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 856 4. A ssem ble snap ring (7) to lock 2nd and 4th speed on countershaft. gears in place. 10. A ssem ble drive gear bearing cap (5), Figure 8, and CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 857 14. R em ove drive g ear bearing ca p (5), Figure 2. with spline of m a in sh aft an d tap or press, if neces- CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 858 17. A pply g ask et cem ent to m a in sh aft rear b earing cap CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 859 4. C o a t O .D . of oil seal (7) with P erm a tex or equiva under shift controls assem bly. lent and assem ble to front of bearing cap. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 860 14. M ain sh a ft (23) with gear assem bly can be rem oved drive gear (16) forw ard from m ainsh aft. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 861 F igu re 1 — 3 -S p e e d A u x ilia r y T ra n sm is sio n (S p ic e r M o d e l 7 2 3 1 A ) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 862 2. Align keyw ay and press overdrive gear (35) on co un tershaft (29). 3. Position spacer sleeve (36) on shaft. Place W oodruff key in groove ad jacen t to snap ring groove. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 863 (7). T ighten the 7 /1 6 -2 0 alloy set screw to case, proceed as follows: 80-85 foot-pounds torque. Secure set screw w ith lockwire (9). A ssem ble new gasket to bearing cap using CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 864 Underdrive G ear.............0.006” -0.011’ 2.3725” -2.3715’ Drive Gear Bore I.D ......Sliding Clutches to Clutch G ears......0.004” -0.007” Countershaft Dia....... . 2.3740” -2.3735’ CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 865 6. Pressure Plate 20. Release Fork Retainer Spring 15. Release Bearing and Support 7. Release Lever 21. Pressure Spring 8. Needle Bearing Rollers Assembly 22. Clutch Housing CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 866 1 / 16-inch moval, overhaul, and installation. of m etal by m achining. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 867 F ig u re 4 — A s s e m b lin g a n d In s ta llin g R e le ase L CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 868 R em ove assem bly from arbor height dim ensions are not as specified, m a k e ad ju stm en t as follows: press. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 869 P IL O T BEARING RE LEASE LEVE R YOKE Type ............Shielded-Ball Bearing Assembly Num ber........ 907059 Bearing Hole D iam e ter...... 0.4438”-0.4448" CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 870 Flywheel Side 6. Pressure Plate 18. Intermediate Plate 12. Retractor Spring 19. Insulator Washer 7. Eyebolt Pin 13. Release Lever 20. Pressure Spring CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK S H O P M A N U A L...
Page 871 R em ove eyebolt pins (7) an d adjusting nuts (10) fro m release levers (fig. 5). 6. R em ove the retracto r springs from clutch cover (fig. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 872 F ig u re 7 — C h e c k in g P re ssu re P late a n d In t e rm e d ia te Plate for surfaces can be cleaned up by m achinin g with rem oval W a r p a g e CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 873 F ig u re 1 1 — R e le a se B e a r in g A s s e m b ly In stalle d CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 874 TRANSMISSION AND CLUTCH 7-128 RELEASE LEVERS CLUTCH RELEASE MECHANISM REPLACEMENT C heck ends of release levers which contact release b e ar See Section 7E of Service Section of this m anual. ing support for wear. Also check fit of pressure plate pins and eye bolt pins in bearing rollers.
Page 875 TRANSMISSION AND CLUTCH 7-129 sert three 9 /1 6 ” -18 x 2" bolts through the cover and IMPORTANT: Levers must be in plane within thread into the adjusting nuts (10) to act as guide bolts 0.031". (fig. 12). W ith guide bolts in place, slowly co m press the assem bly, m aking sure the pressure springs are properly 7.
Page 876 T y p e ................Shielded-Ball C om pression Test (U n d er 142 lb. L o a d ) ..1-25/32” Bearing A ssem bly N o ............954573 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 877 SEC T IO N 9 STEERING CO N TENTS OF THIS SECTIO N Page M echanical S te e rin g ..............9-1 Steering G ear - O v e r h a u l........... 9-1 Pow er S te e rin g ................9-13 Vane T ype H ydraulic P um p O v e r h a u l.......9-21 Slipper Type H y draulic P u m p O v e r h a u l....9-26 Pow er C ylinder - O v e r h a u l..........
Page 878 F ig u re 3 — R e m o v in g P itm a n A rm - S te e rin g G e a r R e m o v e d (T yp ica l) CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 879 5. R em ove lower thrust bearing cone, using bearing re mover plates (J-8176) (fig. 5). CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 880 STEERING 9-4 1 Lock Nut 11 Pitman Arm Nut 23 Lash Adjuster Lock Nut 2 Worm Thrust Bearing 12 Lock Washer 24 Lock Washer Adjuster Oil Seal 13 Pitman Shaft Oil Seal 25 Side Cover 3 Worm Thrust Bearing 14 Housing Bushings 26 Gasket Adjuster 15 Worm Lower Bearing Cup...
Page 881 F ig u re 8 — R e m o v in g S id e C o v e r B u s h in g CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 882 STEERING 9- 6 F ig u re 11-— C h e c k in g L a sh A d ju ste r C le a ra n c e in figure 9. Im provised tool can be m ad e if desired. 2.
Page 883 F ig u re 1 4 — R e m o v in g or in sta llin g N e e d le B e a r in g in H o u s in g CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 884 STEERING 9-8 sem bly by ro tatin g ball nut on shaft w o rm . Do not ro ta te ball nut to end of w o rm threads as this m ay d a m a g e ball guides. If m otion of w orm nut is not free, cause of bind m ust be located an d trouble c o r ...
Page 885 STEERING G EA R SPECIFICATIONS M a k e .................Saginaw Steering Gear Division T y p e .................Recirculating Ball and Sector Nut Model ..............See Chart Above CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 886 Lash Adjuster Shim Thickness . . 0.063", 0.065", 0.067", 0.069" Idler Lever Bushing Width I.D. O.D. Tilt Cab Models ............0.740" .125" 1.312" 0.760" .126" 1.313" CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 887 F ig u re 1 — C o n tro l V a lv e P o w e r S te e r in g G e a r (T y p e 5 5 3 - D V ) (T yp ica l) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 888 F ig u re 2 — C o n tro l V a lv e a n d P o w e r S te e rin g G e a r C o m p o n e n ts CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A ,...
Page 889 F ig u r e 4 — R e m o v in g T hrust B e a r in g R e ta in e r CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 890 O -ring an d reinstall spool im m ediately. D O 4. Using tru-arc pliers, install oil seal retaining ring (2) N O T disassem ble further. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 891 Figure 11— Removing Valve Spool F ig u re 1 0 — L o o se n in g V a lv e Sp o o l CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 892 R eplace d a m p e n e r O -ring F ig u re 1 3 — In sta llin g V a lv e S p o o l S p rin g CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 893 F ig u re 1 6 — In s ta llin g C o n n e c to r in T op C o v e r CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 894 A c c o m p l i s h a ll p r o c e d u r e s p r e v io u s ly d e s c r ib e d F ig u re 1 8 — In sta llin g W o rm S e a l CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 895 -u p w asher (fig. 18). Figu re 21 — A d ju s tin g T hrust B e a r in g P re -L o a d CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 896 9 o ’clock position with shaft (fig. 20). gear in straight ah ead position. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK S H O P M A N U A L...
Page 897 R em ove two pressure plate springs (12) from p u m p d a m ag e d if im m ersed in cleaning solvent. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 898 F ig u re 1— P o w e r Steeriing H y d ra u lic P u m p M o d e l ( 2 3 5 P - 3 6 ) T yp ical CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 899 F ig u re 2 — P o w e r S te e r in g H y d ra u lic P u m p C o m p o n e n t s (T yp ica l) CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK S H O P M A N U A L...
Page 900 (21) (fig. per place, using a 2 -3 /4 inches d ia m eter sleeve, apply 16). CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 901 25. Install filler cap (1) on reservoir and tu b e assem bly F ig u re 1 0 — In s ta llin g P u m p R in g CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 902 4. Use a center punch to m a rk p u m p housing, spanner retaining ring from housing; then rem ove plug with O- CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 903 F ig u re 1 — R e m o v in g P ulle y fro m P u m p S h a ft CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 904 F ig u re 5 — In s ta llin g P u m p S h a f t O il S e a l CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 905 R e p e a t these procedures at opposite end of rod seals, socket end stud ball stud seats, and the cylinder. adjuster screws. CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 906 M a k e ..............Saginaw Steering Gear Division T y p e ..............Recirculating Ball and Sector Nut Model ....................See Chart Above CHEVROLET SERIES 70-80 HEAVY DUTY TRU CK SH O P M A N U A L...
Page 907 . Lock Nut 25-35 Maximum ..Lash A djuster......transmission fluid at 170° F. Control Valve to Steering Gear . Bolt 35-45 CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 908 Maximum . . . 4.8-5.2 gpm of Type “ A ” auto Maximum P S I ...........1100 psi matic transmission fluid Flow Control Valve Spring CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L...
Page 909 STEERING 9-33 SPECIFICATIONS (CONT.) 170°F. temperature when oper Free Length...........3.58" ating pump at 1500 rpm against Compressed Length .... 2.40" under 10 lbs. 50 psi pressure. Bearings must fit: HYDRAULIC P U M P T OR QUE SPECIFICATIONS Shaft D ia m e t e r......0.6245"-0.6250"...
Page 911 R em over & R eplacer (Plain S pring Eye J-22775 * J - 2 1058 Bushing) *L isted in m o re than one section. CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L...
Page 912 C heck ing A d ap ter J-9782-3 R eg u la to r T est A d a p te r *Listed in more than one section. CHEVROLET SERIES 70-80 HEAVY DLJTY TRUCK SH O P M A N U A L...

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