GMC 4000 Series Service Manual

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Page 2 STEERING SYSTEM WHEELS & TIRES SHEET METAL GMC TRUCK & COACH DIVISION CHASSIS ELECTRICAL GENERAL MOTORS CORPORATION AND INSTRUMENTS...
Page 4 GMC Truck. Every effort has been made to include tim ely and adequate information on the various units and systems used on GMC Trucks. The general maintenance and light repair procedures in the various manual sections are the result of extensive service experience.
Page 5 This manual contains “on-the-vehicle” mainte various design and construction differences. nance and light repair information on GMC Truck Manufacturers model or part numbers are used Models listed on page v. Since many truck models in many instances in the “Specifications”...
Page 6 MODEL DATA TRA NSMISSION CLU TCH FRONT AXLE REAR A XLE ENGINE TRU CK OPT. OPT. STD. OPT. STD. OPT. STD. S E R IE S STD. STD. — 435GL 435GD, H150 G161,16121, F070 351C LA, LV-4000 305C 540GD, 540GL T150, G361, 16221 —...
Page 7 VEHICLE MODEL IDENTIFICATION AND WEIGHT RATING PLATE The vehicle identification and weight rating plate is located on th e cab le ft door p illa r of a ll models except “P ” and cowl mod els. Plate location on “P ” and cowl models is determined by the body manufacturer.
Page 8: Table Of Contents
Sec. 0 G M C S E R V I C E M A N U A L Page 1 SECTION O INDEX Subject Page No. Subject Page No. Multi-Purpose Gear Lubricant Symbol "MP" Lubrication Charts Except Steel Tilt Cab Models .....
Page 9: Lubrication Charts Except Steel Tilt Cab Models
Sec. 0 G M C S E R V I C E M A N U A L Page 2 LUBRICATION Figure 1 — Lubrication Chart (Except Steel Tilt C ab M odels)
Page 10 Sec. 0 G M C S E R V I C E M A N U A L Page 3 LUBRICATION LUBRICATION DATA (CHART O N OPPOSITE PAGE) Item Item Remarks Sym. Miles i 2 fittings each s h a c k le ....C 6,000 Spring Shackles and Brackets (1) 1 fitting each b ra ck et....
Page 11: Steel Tilt Cab Models
Sec. 0 G M C S E R V I C E M A N U A L Page 4 LUBRICATION Figure 2 — Lubrication Chart (Steel Tilt C ab M odels)
Page 12 Sec. 0 G M C S E R V I C E M A N U A L Page 5 LUBRICATION LUBRICATION DATA (CHART O N OPPOSITE PAGE) Item Remarks Sym. Miles $ Item 6,000 fittings each s h a c k le .... Spring Shackles and Brackets ....
Page 13: Engine And A Ccessories
Sec. 0 G M C S E R V I C E M A N U A L Page 6 LUBRICATION Item Item Remarks Sym. Miles Engine ............. Keep to "FULL" mark ..Daily Engine Oil Filter ........
Page 14: Capacities Crankcase
Sec. 0 G M C S E R V I C E M A N U A L Page 7 LUBRICATION CAPACITIES CRANKCASE CAPACITIES TRANSMISSION CAPACITIES ENGINE LESS FILTER WITH FILTER PINTS MODEL QTS.* QTS.* U.S. IMPERIAL U.S.. IMP. IMP. U.S.
Page 15: Iscosities
30, etc.), are not recommended, except as a last in GMC Truck and Coach vehicles. For gasoline resort. If used, they should be replaced withS.A.E. engines, if greater stability or detergency is de...
Page 16: Air Cleaners
Sec. 0 G M C S E R V I C E M A N U A L Page 9 LUBRICATION It is recommended that element be changed initially at first oil change and thereafter at intervals in dicated under "Engine Oil Recommendations." Location of oil filter is at left rear on gasoline and diesel models (fig.
Page 17: Paper Element Type
Sec. 0 G M C S E R V I C E M A N U A L Page 10 LUBRICATION cleaning or replacement, use air filter viewer, A.C. Part Number 6484631, which has a special lens for this purpose. A dirt-clogged element pre vents the light from being visible from outside.
Page 18: Air Compressor Air Strainer
G M C S E R V I C E M A N U A L _________________________ page 11 LUBRICATION Figure 1 1 — Crankcase Breather (V6 Gasoline Engine) Paper element type air compressor cleaner is used on all models and should be replaced when element shows visible evidence of damage or a dirt clogged condition or is oil saturated.
Page 19: Crankcase Ventilation (G Asolin E)
Sec. 0 G M C S E R V I C E M A N U A L Page 12 LUBRICATION STARTER third of total hydrocarbon em issions from vehicle. Some starters are equipped with oiler or plug Ventilation valves on "V" engines are threaded at drive end, plug at commutator end, and plug at into cylinder heads, while valve on In-line engines middle bearing.
Page 20: Transmission
Sec. 0 G M C S E R V I C E M A N U A L Page 13 LUBRICATION follows: (1) when axle has not been operated for a long period (2) has been out of normal position or (3) after overhaul.
Page 21: Steering Gear Lubricant - Symbol "Sg
Sec. 0 G M C S E R V I C E M A N U A L Page 14 LUBRICATION STEERING GEAR LUBRICANT (SYMBOL “SG” O N CHARTS) The lubricant indicated by the symbol "SG" is housing when additional lubricant is required; how a special steering gear lubricant.
Page 22: Waterproof Grease - Symbol "S4
Sec. 0 G M C S E R V I C E M A N U A L Page 15 LUBRICATION WATERPROOF GREASE (SYMBOL “S4” O N CHARTS) with this lubricant at the time of assembly. This This type of lubricant should be waterproof lubricant excludes water and dirt from bearing.
Page 23: Automatic Transmission Fluid - Symbol "S19
Sec. 0 G M C S E R V I C E M A N U A L Page 16 LUBRICATION AUTOMATIC TRANSMISSION FLUID (SYMBOL “S I 9 ’ ON CHARTS) The fluid indicated by the symbol "S19" must BLEEDING SYSTEM Whenever a line is disconnected or a pump is be an "Automatic Transmission Fluid,”...
Page 24 Sec. 1 G M C S E R V I C E M A N U A L Page 17 SECTION 1 Gahi and Ai/i GonSitianin^ Maintenance information on subjects common to all cabs, such as painting, checking for water and dust leaks, cab alignment, windshield wipers, and replacement of windshield glass is covered in the "GEN...
Page 25 Sec. 1 G M C S E R V I C E M A N U A L Page 18 GENERAL MAINTENANCE on key shank and the code number is stamped on the WOVEN NYLON FABRIC knock-out portion of the key head. These numbers Soap and toater, regardless of the basic type identify the locks in which the keys are used and of soap, is not recommended for cleaning flat...
Page 26 Sec. 1 G M C S E R V I C E M A N U A L Page 19 GENERAL MAINTENANCE PAINTING To determine the exact location of leak at flooring or cowl, remove floor mat and dash panel pad.
Page 27 Sec. 1 G M C S E R V I C E M A N U A L Page 20 GENERAL MAINTENANCE C le a ra n c e Blocks; (J -9 3 1 6 ) Figure 2 — Checking Class Clearances (Tilt Cab) a.
Page 28 Sec. 1 G M C S E R V I C E M A N U A L Page 21 GENERAL MAINTENANCE rubber seal and seal insert (fig. 1). No sealing INSTALLATION (Fig. 1) compound or cement is used. NOTE: If desired, sealing cement can be ap plied between lip of seal and glass and seal lip at If body prevents access to rear window, glass cab opening flange.
Page 29 Sec. 1 G M C S E R V I C E M A N U A L Page 22 GENERAL MAINTENANCE WIPER A RM TRANSMISSION A N D LINKAGE REPLACEMENT (CONV. CAB MODELS) REMOVAL (Fig. 5) NOTE: Both right and left wiper transmission units with connecting link rod and motor link rod are replaced as an assembly.
Page 30 Sec. 1 G M C S E R V I C E M A N U A L Page 23 GENERAL MAINTENANCE Figure 6 — W iper Motor Installed (Conventional Cab) may be restricted when motor is started, resulting pivot shaft. Remove arm and driver. in a blown fuse.
Page 31 Sec. 1 G M C S E R V I C E M A N U A L Page 24 GENERAL MAINTENANCE Tran sm ission G ro u n d Strap M o u n t in g Bracket Sh aft A s s e m b ly | Sh aft H o u sin g A s s e m b ly Shaft H o u sin g A ss e m b ly...
Page 32 Sec. 1 G M C S E R V I C E M A N U A L Page 25 GENERAL MAINTENANCE SHUNT W IN D IN G # 3 TERMINAL SERIES W IN D IN G TERMINAL WIPER TERMINAL BOARD # 2 TERMINAL D A S H SW ITC H W A S H E R U N IT...
Page 33 Sec. 1 G M C S E R V I C E M A N U A L Page 26 GENERAL MAINTENANCE NOTE: Terminals Are Numbered Series W in d in g Shunt W in d in g For Purposes of Explanation LO SPEED—As Shown i—...
Page 34 Sec. 1 G M C S E R V I C E M A N U A L Page 27 GENERAL MAINTENANCE 10 Gear Box Housing 1 Nut 11 Brush Plate Assy, and 2 Crank Arm Mounting Brackets 3 Seal Cap 12 Brushes 4 Retaining Ring 13 Wave Washers...
Page 35 Sec. 1 G M C S E R V I C E M A N U A L Page 28 GENERAL MAINTENANCE Figure 15— W asher Pum p Attaching Screws Figure 14— End Play W ave W asher Installation rotates whenever the wiper motor is running. P ro gramming is accomplished electrically and mech...
Page 36 Sec. 1 G M C S E R V I C E M A N U A L Page 29 GENERAL MAINTENANCE 3. If all items in Step 2 check out, start wiper motor only, then push washer button and listen for Figure 16—...
Page 37 Sec. 1 G M C S E R V I C E M A N U A L Page 30 GENERAL MAINTENANCE NOTE: Ratchet pawl spring removed in above view 1 Coil Term inals 12 Solenoid Coil Assem bly 7 Ratchet Wheel 2 Solenoid Plunger 13 Pivot Pin 8 Valve A ssy.
Page 38 Sec. 1 G M C S E R V I C E M A N U A L Page 31 Go-twesitiosial Gab Contents of this section are listed in Index below: Subject Page No. Cab Description ............Cab M o u n tin g s..............S e a t s .................
Page 39 Sec. 1 G M C S E R V I C E M A N U A L Page 32 CONVENTIONAL CAB SE A T B A C K A D JU S T IN G STUD A N D N U TS FO RE A N D AFT A D JU S T IN G LEVER Figure 2 —...
Page 40 Sec. 1 G M C S E R V I C E M A N U A L Page 33 CONVENTIONAL CAB Figure 5 — C a b Door Hinges and Check Link Figure 6 — Door Clearances INSTALLATION (Fig. 5) 1.
Page 41 Sec. 1 G M C S E R V I C E M A N U A L Page 34 CONVENTIONAL CAB Figure 7— Door Striker Bolt and Washers washer on door pillar using pencil or crayon. Insert a 5/16-inch hex wrench into head of Figure 8 —...
Page 42 Sec. 1 G M C S E R V I C E M A N U A L Page 35 CONVENTIONAL CAB APPLY PAINT OR GREASE STRIKER BOLT TO EDGE OF LOCK C A M 1 / 1 6 " BELOW LINE DAB OF PAINT OR GREASE SCRIBE H O R IZO N TAL...
Page 43 Sec. 1 G M C S E R V I C E M A N U A L Page 36 CONVENTIONAL CAB Figure 11 — D oor Check Installed Figure 13— Installing Access Panel Insert 2. Apply cement to cab flange surfaces, then areas will prevent weatherstrip from sticking or position seal to cab.
Page 44 Sec. 1 G M C S E R V I C E M A N U A L Page 37 CONVENTIONAL CAB Figure 15— Door Handle Disassembly DOOR LOCK CYLINDER REPLACEMENT REMOVAL (Fig. 17) Using flat blade screwdriver, pry retainer Figure 14—...
Page 45 Sec. 1 G M C S E R V I C E M A N U A L Page 38 CONVENTIONAL CAB RETAINER RETAINER SCREWDRIVER IN S T A L L IN G C Y L IN D E R R E M O V IN G RET A IN ER Figure 17—...
Page 46 Sec. 1 G M C S E R V I C E M A N U A L Page 39 CONVENTIONAL CAB THREADED LO C KIN G KN O B HANDLE P O SIT IO N M A RK LOCKING ROD ESC U T C H E O N PLATE REMOTE CONTROL ATTACHING SCREW S...
Page 47 PageUp__________________________ G M C S E R V I C E M A N U A L CONVENTIONAL C A B ^ Figure 2 0 — Adjusting Vent W indow Tension Figure 2 2 — Replacing Vent W in do w as shown in figure 20, turn adjustment nut with a ^-inch speed wrench to obtain five to seven pounds torque, while moving vent window from a ten-...
Page 48 Sec. 1 G M C S E R V I C E M A N U A L Page 41 CONVENTIONAL CAB Figure 2 3 — Replacing Door W in d o w Class Assem bly door and rotate it to locate in position (fig. 22). 2.
Page 49 Sec. 1 G M C S E R V I C E M A N U A L Page 42 CONVENTIONAL CAB Figure 2 7 — Removing Glass Horizontal Seals remove the door window assembly and the vent window assembly as directed previously under Figure 25 —...
Page 50 Sec. 1 G M C S E R V I C E M A N U A L Page 43 CONVENTIONAL CAB DOOR W IN D O W GLASS HORIZONTAL seals from door panel in manner shown in figure 27. Pry a small amount at each fastener to prevent SEAL REPLACEMENT seal channel distortion.
Page 51 Sec. 1 G M C S E R V I C E M A N U A L Page 44 CONVENTIONAL CAB AIR FLOW! REMOVAL (Fig. 28) 1. Drain the cooling system to just below level SPEED CONTROL of heater core fittings. RESISTOR UNIT 2.
Page 52 Sec. 1 G M C S E R V I C E M A N U A L Page 45 CONVENTIONAL CAB ADAPTER ASSEMBLY BLOWER A N D HEATER CORE ASSEMBLY M O TO R G R O U N D WIRE HEATER U N IT M O U N T IN G AIR DISTRIBUTOR ASSEMBLY...
Page 53 Sec. 1 G M C S E R V I C E M A N U A L Page 46 CONVENTIONAL CAB 4. At front side of heater core housing, re ROTATE TO C H A N G E move protective shield and the small spring-type CABLE LENGTH retaining washer from "TEMP"...
Page 54 Sec. 1 G M C S E R V I C E M A N U A L Page 47 CONVENTIONAL CAB AIR DISTRIBUTOR REPLACEMENT (HEAVY DUTY AIR-FLOW HEATER) The air distributor can be readily replaced after disconnecting the attaching air hoses and the "DEFROST"...
Page 55 Sec. 1 ____________G M C S E R V I C E M A N U A L Page 48____________ CONVENTIONAL NOTE For all "Air Conditioning" information, refer to separate "AIR CONDITIONING" sub-section at end of this section.
Page 56 Sec. 1 G M C S E R V I C E M A N U A L Page 49 l i l t Gab Maintenance information on windshield wipers, windshield and rear window glass replacement, and cab painting is explained in "GENERAL MAINTENANCE"...
Page 57 PageUp___________ G M C S E R V I C E M A N U A L TILT CAB 2. At right rear of cab remove safety chain hook. 3. While holding safety catch release rod to the right, pull hold-down release lever out and up ward until hold-down catch becomes disengaged and rear of cab raises from mount (fig.
Page 58 Sec. 1 G M C S E R V I C E M A N U A L Page 51 TILT CAB .j Four A tta ch in g Studs / (Stud N u ts A cce ssible from U nd e r C ab) Figure 5 —...
Page 59 Sec. 1 G M C S E R V I C E M A N U A L Page 52 TILT CAB Figure 7 — Door Hinges If door has been replaced, adjustments should be made in sequence described in the following paragraphs: DOORS REPOSITION DOOR "UP"...
Page 60 Sec. 1 G M C S E R V I C E M A N U A L Page 53 TILT CAB SPACER PLASTIC W ASH ER TAPPED FLOATING STRIKER BOLT PLATE A N D W ASH ER Figure 8 — Door Striker Bolt and W ashers 3.
Page 61 Sec. 1 G M C S E R V I C E M A N U A L Page 54 TILT CAB DEPRESS RETAINER THEN ROTATE Figure 10— Striker Bolt Alignm ent are available in two thicknesses: 5/64-inch and 5/32-inch. Make sure the thin plastic washer is located next to cab pillar.
Page 62 Sec. 1 G M C S E R V I C E M A N U A L Page 55 TILT CAB Figure 14— Door Lock Cylinder Replacement tainer into grooves of lock cylinder body. Be cer tain legs of retainer are fully engaged. It may be Figure 13—...
Page 63 Sec. 1 G M C S E R V I C E M A N U A L Page 56 TILT CAB IN T E R IO R O F D O O R D O O R C O N S T R U C T I O N 1 Vent Window Glass 9 Division Channel Lower 15 Door Lock Remote Control...
Page 64 Sec. 1 G M C S E R V I C E M A N U A L Page 57 TILT CAB R E G U L A T O R A R M T-5805 Figure 18— Rem oving Regulator Arm from Track special locking-type screw s which attach lock mechanism to door frame.
Page 65 Sec. 1 G M C S E R V I C E M A N U A L Page 58 TILT CAB A S SE M B L Y Figure 2 0 — Rem oving Door W in d o w Class 3.
Page 66 Sec. 1 G M C S E R V I C E M A N U A L Page 59 TILT CAB P ivot Scre w D iv is io n V e n t W i n d o w Top V e n t W in d o w G la ss C h a n n e l R e ta in in g Sc re w s...
Page 67 Sec. 1 G M C S E R V I C E M A N U A L Page 60 TILT CAB to remove old glazing rubber, rust, or other for eign matter. 2. Position new glazing rubber (soapstone side away from glass) around edge of glass.
Page 68 Sec. 1 G M C S E R V I C E M A N U A L Page 61 TILT CAB making sure corners of seal engage respective 3. Apply coat of weatherstrip adhesive to seal and seal surfaces of door as directed by manu corners of door.
Page 69 Sec. 1 G M C S E R V I C E M A N U A L Page 62 TILT CAB Figure 3 1 — Rear H o ld -D o w n Catch on W oo d Block trie connectors that junction cab with the chassis.
Page 70 Sec. 1 G M C S E R V I C E M A N U A L Page 63 TILT CAB C a b Right ------- — Sill Brackets.. Heater Line Connec t i ons — " A cce le rator Control. C on n ections Steering Connection 1...
Page 71 Sec. 1 G M C S E R V I C E M A N U A L Page 64 TILT CAB C a b Su p p o rt Torsio n B a r Bracket Stop Bracket C la m p Bolt— T o rq u e To 6 5 To 7 5 Ft.-Lbs.
Page 72 Sec. 1 G M C S E R V I C E M A N U A L Page 65 (lady MountitKfi PLATFORM BODY MOUNTINGS Before any body mounting is attempted, this tersink longitudinal s ills just enough to clear rivet heads.
Page 73 Sec. 1 G M C S E R V I C E M A N U A L Page 66 BODY M OUNTINGS STUD TYPE M O U N T IN G T A P P E D PLATE TYPE M O U N T IN G U-BOLT TYPE M O U N T IN G 1 Lock Nut 6 Spacer Block...
Page 74 Sec. 1 G M C S E R V I C E M A N U A L Page 67 BODY M OUNTINGS of nuts at top of sill, tapped plate, as shown in figure 2 can be used. 4. Insert a block of hard, dry wood (with grain running up and down) in channel of frame at each mounting.
Page 75 Sec. 1 ________________________G M C S E R V I C E M A N U A L Page 68 BODY MOUNTINGS IMPORTANT DO NOT drill additional holes in frame. Refer to F R A M E (SEC. 2) for additional cautions.
Page 76 Sec. 1 G M C S E R V I C E M A N U A L Page 69 A il G&n&itiosiincj, (CONVENTIONAL CAB MODELS) This sub-section contains service information on the following: Subject Page No. General Information ................Operating Instructions ...............
Page 77 Sec. 1 G M C S E R V I C E M A N U A L Page 70 AIR CONDITIONING with requirements of evaporator. COOLING SYSTEM This system consists of three major compon The suction throttling valve (S.T.V.) is de ents located at the cowl and dash assembly.
Page 78 Sec. 1 G M C S E R V I C E M A N U A L Page 71 AIR CONDITIONING temperature of incoming air. Should defogging of When cab begins to cool, close windows tightly and windshield be required, open door ventilator win move ”AIR"...
Page 79 Sec. 1 G M C S E R V I C E M A N U A L Page 72 AIR CONDITIONING SYSTEM OPERATION Contents of This Sub-Section are as Follows: Subject Page No. General Operation ................Fundamental Principles of Refrigeration ........
Page 80 Sec. 1 G M C S E R V I C E M A N U A L Page 73 AIR CONDITIONING This is due to the fact that the cover is not as hot evaporates and cools so rapidly it will cause an as the steam.
Page 81 Sec. 1 G M C S E R V I C E M A N U A L Page 74_________________ AIR CONDITIONING Figure 4 — Schematic of Refrigerant Cycle poisonous gas. The same gas will attack all bright refrigerating system is as follows: metal surfaces.
Page 82 Sec. 1 G M C S E R V I C E M A N U A L Page 75 AIR CONDITIONING from the evaporator through the suction throttling valve, then back through the suction line to com pressor thus completing the cycle. AIR CIRCULATION Air circulation is common to both the heating and air conditioning system s.
Page 83 Sec. 1 G M C S E R V I C E M A N U A L Page 76 AIR CONDITIONING (Pressure under the diaphragm is evaporator p res completely vaporize and then warm (superheat) sure. It reaches this area by means of clearance 10.6°F.
Page 84 Qpp 1 G M C S E R V I C E M A N U A L __________________ Page 77 AIlT CONDITIONING M AINSHAFT PISTON DRIVE BALL SU C T IO N ^ O N T ^ SHAFT PULLEY THRUST O -RIN G SEAL SEAL...
Page 85 Sec. 1 G M C S E R V I C E M A N U A L Page 78 AIR CONDITIONING When the "AIR COND." knob is placed to "OFF," the electrical circuit to the com pressor clutch is opened and the magnetic pull on the clutch no long...
Page 86 Sec. 1 G M C S E R V I C E M A N U A L Page 79 AIR CONDITIONING any moisture that might be present in the system white felt bag that is not attached to anything but after assembly.
Page 87 Sec. 1 G M C S E R V I C E M A N U A L Page 80_________________ AIR CONDITIONING TEST READINGS Ambient A ir in Degrees F. (In A u xiliary Fan Air Blast 2" Ahead of Condenser). A ir Quality Arid Humid...
Page 88 Sec. 1 G M C S E R V I C E M A N U A L Page 81 AIR CONDITIONING Testing to determine if the discharge air temp erature, suction pressure, and discharge pressure meet the specifications at a particular ambient condition is called a "Performance Test."...
Page 89 Sec. 1 G M C S E R V I C E M A N U A L Page 82 AIR CONDITIONING auxiliary fan air stream to measure wet bulb 9. Place transmission lever in "Neutral,"with temperature. parking brake on. 6.
Page 90 Sec. 1 G M C S E R V I C E M A N U A L Page 83 AIR CONDITIONING When hissing ceases (indicating all refrig 12. Allow engine to run for 10 minutes, or until erant has escaped) close valves on manifold gauge stabilized.
Page 91 Sec. 1 G M C S E R V I C E M A N U A L Page 84________________ AIR CONDITIONING C OM PRESSO R ______ SUCTION THROTTLING VALVE ‘C O N D EN SER -5725-04 , J-6272 -01 DRUM ^ "...
Page 92 Sec. 1 G M C S E R V I C E M A N U A L Page 85 AIR CONDITIONING b. Connect flexible line from center fitting of 3. Place refrigerant drum (in pail of water) on the gauge set to refrigerant container (container sca les (bathroom or commercial, preferably com ...
Page 93 Sec. 1 G M C S E R V I C E M A N U A L Page 86 AIR CONDITIONING gauge set and "crack" valve at can opener (for a though the proper amount of refrigerant is in the second or two) to force air from theline.
Page 94 Sec. 1 G M C S E R V I C E M A N U A L Page 87 AIR CONDITIONING tions should be lowered by 1 inch. Example: At SERVICE STATION METHOD The J-8393 Deluxe Portable Air Conditioner 5000 ft.
Page 95 Sec. 1 G M C S E R V I C E M A N U A L Page 88 AIR CONDITIONING 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 r e ...
Page 96 Sec. 1 G M C S E R V I C E M A N U A L Page 89 AIR CONDITIONING com pressor. The amount of oil to put back into the com pressor is found as follows: DO NOT add any more oil than is necessary or maximum cooling will be reduced.
Page 97 Sec. 1 G M C S E R V I C E M A N U A L Page 90 AIR CONDITIONING (hand tight), then open valve quickly, admitting a closure plate which can be improvised and in several short blasts. stalled as shown.
Page 98 Sec. 1 G M C S E R V I C E M A N U A L Page 91 AIR CONDITIONING dence of a major leak, indicating that little or no oil has been lost from the system . (Minor leak in dicating very slow leakage.) If oil drained in step 1 previously contains any foreign material such as chips, or there is...
Page 99 Sec. 1 G M C S E R V I C E M A N U A L Page 92 AIR CONDITIONING figure 15 for proper positioning of hose and hose clamp. NOTE: The initial clamp screw torque is 25 to 32 inch-pounds.
Page 100 Sec. 1 G M C S E R V I C E M A N U A L Page 93 AIR CONDITIONING EXPANSION VALVE REPLACEMENT EVAPORATOR HEATER CORE ASSEMBLY REPLACEMENT NOTE: When refrigeration system components NOTE: When refrigeration system components other than the com pressor are replaced, the com...
Page 101 Sec. 1 G M C S E R V I C E M A N U A L Page 94 AIR CONDITIONING INSPECTING COMPRESSOR If there is no visible evidence of damage, ro tate com pressor shaft to test for normal reaction. A quick check for broken reed valves is to turn com pressor shaft (using box end wrench on com...
Page 102 Sec. 1 G M C S E R V I C E M A N U A L Page 95 AIR CONDITIONING SPECIFICATIONS Refrigerant C a p a city ..............3 lbs. 4 oz. Refrigerant Oil Capacity (entire sy s te m )......... 11 oz. Compressor Clutch Coil Current (m axim um dem an d)........3.2 A m ps.'at 12v.
Page 103 Sec. 1 G M C S E R V I C E M A N U A L Page 96 AIR CONDITIONING Inspect system for visual de- Check blower operation. fe c ts. Check airt temperature. HIGH AIR NORMAL AIR AIR TEMPERATURE TEMPERATURE VARIES...
Page 104 Sec. 1 G M C S E R V I C E M A N U A L Page 97 AIR CONDITIONING INSUFFICIENT CO O LING D IA G N O SIS CHART NOTES (Used in Conjunction With Chart on Opposite Page) NOTE “A ”...
Page 105 Sec. 1 Page 98 G M C S E R V I C E M A N U A L AIR CONDITIONING REFRIGERANT LINE CONNECTIONS TORQUE SPECIFICATIONS OUTSIDE DIAMETER TORQUE FT.-LBS. TORQUE FT.-LBS. OF METAL TUBING (STEEL) ALUMINUM OR COPPER (INCHES) 10 - 15 5 - 7...
Page 106 Sec. 2 G M C S E R V I C E M A N U A L Page 99 SECTION 2 f y t i a m GENERAL must be used on the right rail. The illustration (fig. 1) is used merely to serve as a guide in the selection of checking points "M."...
Page 107 Rear axle alignment with respect to the frame is correct if "ER" equals "EL" and "GR" The standard models as quoted in the GMC equals "GL." NOTE: Alignment may appear to be Data Book describe the physical dimension of the off if rear ends of frame rails are not cut-off frame rail and specify the type of material used.
Page 108 Sec. 2 G M C S E R V I C E M A N U A L Page 101 FRAME Listed under "Specifications” at the end of E xcessive bending moment failures are caus this section are selected sizes of welding elec ed by overload, improper weight distribution, or trodes for use in repairing frame side rails.
Page 109 Sec. 2 Page 102 G M C S E R V I C E M A N U A L FRAME is not an approved installation as high str ess con be pointed out that dump trucks, as an example, centration may develop.
Page 110 Sec. 2 G M C S E R V I C E M A N U A L Page 103 FRAME a. Continuous Fillet Weld - This is used to Improper reinforcement or attachment of r e weld a continuous bead along a reinforcement plac inforcement may cause more difficulty than the ed on the web section of the frame rail or for add...
Page 111 Sec. 2 G M C S E R V I C E M A N U A L Page 104 FRAME sary to align the frame and level the rails before repairing the frame.) 3. Vee grind the entire length of the crack from the starting point to the quarter inch hole at the extreme end.
Page 112 6 to 8 inch intervals. Do reinforcement has been released in six-foot lengths not weld across the end or along the flange edges. through the Factory Warehouse under GMC Part Ends should be cut at an angle and edges of plug Number 2446489.
Page 113 Sec. 2 G M C S E R V I C E M A N U A L Page 106 FRAME — CAUTION — GENERAL RULES Listed below are general rules which apply to frame repair and reinforcem ents. Most of these rules are discussed earlier in this section;...
Page 114 Sec. 2 G M C S E R V I C E M A N U A L Page 107 FRAME FRAME SPECIFICATIONS PLUG WELD CHART ELECTRODE CHARTS E-7011 Thickness of Diameter Depth Flat Welding Material of Plug Plug Available Current ...
Page 115 Sec. 2 ______________________ G M C S E R V I C E M A N U A L Page 108 FRAME Frame repairs should be undertaken only by competent mechanics, and only the recommended materials should be used.
Page 116 Sec. 3A G M C S E R V I C E M A N U A L Page 109 SECTION 3 This group is divided into four sub-sections as shown in index below: Section Page No. Front End Alignment ..........
Page 117 Sec. 3A G M C S E R V I C E M A N U A L Page 110 FRONT END ALIGNMENT G Caster A n gle Vertical K ing Pin $ FR O N T A X L E CASTER C A M B E R A N D K IN G P IN IN C L IN A T IO N T O E -IN K IN G PIN IN C L IN A T IO N...
Page 118 Sec. 3A G M C S E R V I C E M A N U A L Page 111 FRONT END ALIGNMENT cylinder to tie rod ”U" bolt nuts. With both tie rod knuckle is bent and should be replaced. Excessive ends in same plane, tighten clamp bolts securely.
Page 119 Sec. 3A G M C S E R V I C E M A N U A L Page 112 FRONT END ALIGNMENT KING PIN INCLINATION (c) - Negative frame angle must be subtracted from negative caster reading. (d) - Positive frame angle must be added to King pin inclination is the amount that top of negative caster reading.
Page 120 Sec. 3B G M C S E R V I C E M A N U A L Page 113 SECTION 3B fy n a n t A x lz Axle steering knuckles are constructed as moving assembly from vehicle if necessary. Minor shown in figure 2.
Page 121 Sec. 3B G M C S E R V I C E M A N U A L Page 114 FRONT AXLE Steering knuckles are equipped with bushings of BRAKES" (SEC. 5A) of this manual. polycarbonate construction and they can be washed 3.
Page 122 Sec. 3B G M C S E R V I C E M A N U A L Page 115 FRONT AXLE or fractures. If Magna-Flux equipment is avail THRUST WASHERS OR BEARINGS Examine thrust washers or bearings for ex able, use this method to inspect knuckles for frac...
Page 123 S ec. 3B G M C S E R V I C E M A N U A L Page 116 FRONT AXLE SPECIFICATIONS FRONT AXLE SPECIFICATIONS F050 AXLE MODEL F055 F070 King P in — Len g th ..............623/64"...
Page 124 GENERAL SPRING MAINTENANCE nut, and washer; withdraw eye bolt from bracket and spring eye. 5. On all L-4000 Series, remove bolt, bolt LUBRICATION retainer, and rebound pin at rear hanger. On all Spring leaves are lubricated at time of a s...
Page 125 Sec. 3C G M C S E R V I C E M A N U A L Page 118 FRONT SPRINGS ■=r---- FRONT BRACKET ' NUTS 3 5 - 5 5 Ft. Lbs. Torque ( E 4 5 0 0 - S 5 5 0 0 M o de ls) 3 0 - 4 0 Ft.
Page 126 Sec. 3C G M C S E R V I C E M A N U A L Page 119 FRONT SPRINGS B U M P E R S H O C K A B S O R B E R U -B O L T S P A C E R U -B O L T S P R IN G...
Page 127 Sec. 3C G M C S E R V I C E M A N U A L Page 120 FRONT SPRINGS Figure 9 — Installed Position of Offset Bushing (PS4500) Figure 7— Rem oving Rubber Type Eye Bushing (PS4500) used) and caster spacer (when used) on axle pad, raise axle to springy making sure spring center bolt or dowel pin engages hole in axle pad.
Page 128 Sec. 3C G M C S E R V I C E M A N U A L Page 121 FRONT SPRINGS SPECIFICATIONS TORQUE SPECIFICATIONS FT. LBS. U-BOLT NUTS All 4000 S e r ie s ..........................................135-150 PS4500 .......................................... 105-130 E-5500-6500 S eries, S6500 S e rie s............................
Page 129 Sec. 3D G M C S E R V I C E M A N U A L Page 122 SECTION 3D cJluhl and (iea'Unai. DESCRIPTION overheat and wear rapidly. Loose adjustment will cause pounding and will also contribute to steering Front hubs are mounted on steering knuckle difficulties, uneven tire wear, and inefficient brakes.
Page 130 Sec. 3D G M C S E R V I C E M A N U A L Page 123 FRONT HUBS A N D BEARINGS hub as directed in LUBRICATION (SEC. 0) of this front axle until wheels clear floor. manual.
Page 131 Sec. 3D G M C S E R V I C E M A N U A L Page 124 FRONT HUBS A N D BEARINGS a. Separate the drums and hub by removing damage. Non-demountable brake drums can be re finished while mounted on hubs.
Page 132 Sec. 4A G M C S E R V I C E M A N U A L Page 125 SECTION 4 HeaA, S u A n e fiA ia n This section is divided into three sub-sections as shown in index below: Section Page No.
Page 133 Sec. 4A G M C S E R V I C E M A N U A L Page 126 REAR AXLE A N D CONTROLS axle. When the shift is completed, the ends of the spring come together leaving the original tension on the spring.
Page 134 Sec. 4A G M C S E R V I C E M A N U A L Page 127 REAR AXLE AND CONTROLS rear axle to vacuum and opposite side to atmos- to speedometer adapter causing rod to move inward phere.
Page 135 Sec. 4A G M C S E R V I C E M A N U A L Page 128 REAR AXLE A N D CONTROLS HIGH SPEED SHIFTING With shift control button on gearshift lever When shifting from "Lo" to "Hi" the operator up, in "Hi"...
Page 136 Sec. 4A G M C S E R V I C E M A N U A L Page 129 REAR AXLE AND CONTROLS circuit breaker is faulty. Turn chalk marks on both wheels so that 6. At chassis junction, remove both w ires, marks are level with axle and toward rear of ve...
Page 137 Sec. 4A G M C S E R V I C E M A N U A L Page 130 REAR AXLE A N D CONTROLS line connections with hydraulic brake fluid. If leak being sure to change shift button. exists, fluid will be drawn into connection with en...
Page 138 Sec. 4A G M C S E R V I C E M A N U A L Page 131 REAR AXLE AN D CONTROLS in "REAR HUBS AND BEARINGS" (SEC. 4C). Roll INSTALLATION 1. Install new differential carrier to housing axle into position under vehicle.
Page 139 Sec. 4A G M C S E R V I C E M A N U A L Page 132 REAR AXLE A N D CONTROLS REMOVAL 1. Remove propeller shaft from yoke at axle as directed in "PROPELLER SHAFTS" (SEC. 4D). 2.
Page 140 Sec. 4A G M C S E R V I C E M A N U A L Page 133 REAR AXLE A N D CONTROLS screw s and lock washers, tightened securely. Remove lock nuts and the two w ires from Coat lip of oil seal with axle lubricant, then shift housing.
Page 141 Sec. 4A G M C S E R V I C E M A N U A L Page 134 REAR AXLE A N D CONTROLS 2. Install w ires to outside term inals. The long black ribbed wire is attached to bottom terminal. Harness is clipped to cable clip on housing.
Page 142 Sec. 4A G M C S E R V I C E M A N U A L Page 135 REAR AXLE A N D CONTROLS stud nuts, then remove shift unit from axle. Remove wire cable clip from shift unit cover.
Page 143 Sec. 4A G M C S E R V I C E M A N U A L Page 136 REAR AXLE A N D CONTROLS mount assembly in vise as shown in figure 19. CLEANING AND INSPECTION Place a short piece of rod in hub of spring winding Clean all parts except motor in cleaning so l...
Page 144 Sec. 4A G M C S E R V I C E M A N U A L Page 137 REAR AXLE A N D CONTROLS Drive Screw The drive screw assembly is serviced only as an assembly. While holding the nut, rotate the screw from one end to the other.
Page 145 Sec. 4A G M C S E R V I C E M A N U A L Page 138 REAR AXLE A N D CONTROLS and fiber contact bumper down toward switch, position the slots of winding lever over the drive nut.
Page 146 Sec. 4A G M C S E R V I C E M A N U A L Page 139 REAR AXLE AND CONTROLS Inspect poppet discs and replace if not in 3. Attach motor w ires to switch term inals. new condition, since these items are included in The red or longer wire attaches to bottom term ...
Page 147 Sec. 4A G M C S E R V I C E M A N U A L Page 140 REAR AXLE A N D CONTROLS 4. Attach intake manifold, air cleaner, speed ometer shifter changer, and shift chamber lines to valve in their original location.
Page 148 Sec. 4A G M C S E R V I C E M A N U A L Page 141 REAR AXLE A N D CONTROLS ASSEMBLY (Fig. 24) 1. Install washer, long spacer, spring, washer, short spacer, and nut on push rod. 2.
Page 149 Sec. 4A G M C S E R V I C E M A N U A L Page 142 REAR AXLE AND CONTROLS 4. Remove two nuts and lock washers from studs (fig. 27) attaching chamber mounting flange to mounting sleeve and carrier. Remove chamber assembly.
Page 150 Sec. 4A G M C S E R V I C E M A N U A L Page 143 REAR AXLE AND CONTROLS SPEEDOMETER ADAPTER Remove four screws attaching body to bracket. Remove body, spring, and diaphragm and SHIFT DIAPHRAGM rod assembly from bracket.
Page 151 Sec. 4A G M C S E R V I C E M A N U A L Page 144 REAR AXLE AND CONTROLS REAR AXLE TORQUE SPECIFICATIONS IT E M T O R Q U E ( F T . L B .) D R IV E P IN IO N Y O K E N U T Eaton lV fi"-1 8 ........................
Page 152 Sec. 4B G M C S E R V I C E M A N U A L Page 145 SECTION 4B H e a A g m o bushings that are rubber-mounted do not require Progressive type, two-stage rear springs, as used on all 4000 and PS4500 Series (fig.
Page 153 Sec. 4B G M C S E R V I C E M A N U A L Page 146 REAR SPRINGS AND SUSPENSION AUXILIARY SPRING ASSEMBLY Figure 2 — Rear Springs Installed (Typical for “ £ ” and “S” Models) Remove rear wheels to provide access to spring into tapped hole at end of rebound pin, then remove assem bly.
Page 154 Sec. 4B G M C S E R V I C E M A N U A L Page 147 REAR SPRINGS AND SUSPENSION J-2 1 0 5 8 Figure 4 — Rem oving Rubber-Type Eye Bushing Figure 5 — Installing Rubber-Type Eye Bushing 4.
Page 155 Sec. 4B G M C S E R V I C E M A N U A L Page 148 REAR SPRINGS AND SUSPENSION are limited to replacement of rubber mounting CAUTION: When replacing a shock grommets and periodically tightening all mount- absorber, check the model number stamp...
Page 156 Sec. 4C G M C S E R V I C E M A N U A L Page 149 SECTION 4C fleoA a n d feea'dnaA. DESCRIPTION ADJUSTMENT 1. Jack up axle and remove axle shaft as directed in "REAR AXLES" (SEC. 4A) of this manual. Rear hubs on all series trucks are mounted to 2.
Page 157 Sec. 4C Page 150 G M C S E R V I C E M A N U A L REAR HUBS AND BEARINGS H I 10, H I 35, A X L E S — w / D IS C W H E E L S H I 50, T 150, G 1 6 1 , G 36 1 A X L E S - w / C A S T W H E E L S 16 12 1, 1 6 22 1, 17 12 1, 17221 A X L E S - w / D I S C W H EEL S 20 Stud...
Page 158 Sec. 4C G M C S E R V I C E M A N U A L Page 151 REAR HUBS AND BEARINGS nately drive on opposite sides of spacer to avoid Install axle shaft as directed in "REAR AXLES"...
Page 159 Sec. 4C G M C S E R V I C E M A N U A L Page 152 REAR HUBS AND BEARINGS REPAIR then p ress new bolts into place, making sure bolts are a tight fit. If all bolts were removed, be sure Bearing Cup Replacement that hub oil deflector is in position under bolt heads.
Page 160 Sec. 4C G M C S E R V I C E M A N U A L Page 153 REAR HUBS AND BEARINGS assembly; then install outer bearing cup with thin seats against bearing cup, on types shown in Views edge of cup toward outer end of hub until it clears B, and C in figure 2, make sure seal ring is in the snap ring groove, using a suitable sleeve.
Page 161 Sec. 4C _______________________G M C S E R V I C E M A N U A L Page 154 REAR HUBS AND BEARINGS IMPORTANT At installation, always coat the oil seal bore in hub with a thin layer of non-hardening sealing compound and always be sure that the oil seals are properly seated.
Page 162 Sec. 4D G M C S E R V I C E M A N U A L Page 155 SECTION 4D Pnxm>elle'i SUajjti DESCRIPTION onto end of yoke. Fixed yoke may be either welded to propeller shaft tube or it may be splined to a Power is transmitted from transmission to stub shaft and secured with a nut and cotter pin rear axle through one or more propeller shaft and...
Page 163 Sec. 4D G M C S E R V I C E M A N U A L Page 156 PROPELLER SHAFTS SERVICE DIAGNOSIS CHART CONDITION CORRECTION POSSIBLE CAUSE Propeller Shaft Vibration 1. Check for Foreign Material 1. Propeller Shaft Out of Balance. on Propeller Shaft.
Page 164 Sec. 4D G M C S E R V I C E M A N U A L Page 157 PROPELLER SHAFTS \ y r w w ) 1 ■ J J _ j \ J " 1 Nut 5 Cushion Retainer 9 Bearing Assembly 2 Yoke 6 Center Bearing Support...
Page 165 Sec. 4D G M C S E R V I C E M A N U A L Page 158 PROPELLER SHAFTS Propeller Shaft Guard Propeller Shaft Center Bearing Support Dust Cap Washer (Steel) Washer (Cork) Bolt Rear Axle T P M -9 1 4 2 -1 Figure 3 —...
Page 166 Sec. 4D G M C S E R V I C E M A N U A L Page 159 PROPELLER SHAFTS ASSEMBLY OPERATIONS 3. Thread dust cap onto end of slip yoke. Tighten dust cap by hand only; use of wrench will CENTER BEARING ASSEMBLY damage cork or felt washer.
Page 167 Sec. 4D G M C S E R V I C E M A N U A L Page 160 PROPELLER SHAFTS SPECIFICATIONS UNIVERSAL JOINT APPLICATION Th e following tabulation lists universal jo in ts used with standard equipm ent only. Refer to parts book for universal jo in ts used with optional equipm ent.
Page 168 Sec. 5A G M C S E R V I C E M A N U A L Page 161 SECTION 5 fetvcJ zei This group is divided into three sections as shown in Index below: Section Page No. Hydraulic B r a k e s ............ Air Brakes ..............
Page 169: Brake System Maintenance
Sec. 5A G M C S E R V I C E M A N U A L Page 162 HYDRAULIC BRAKES Air Cleaner Vacuum Gauge Master Cylinder Vacuum Line From Engine (From Vacuum Pump on D iesel) Brake Pedal Vacuum Power Cylinder Vacuum Line From Engine to Control Valve...
Page 170 Sec. 5A G M C S E R V I C E M A N U A L Page 163 HYDRAULIC BRAKES BRAKE ADJUSTMENT MODEL CHART NOTE: Wheel bearings must be properly ad justed before attempting to adjust brake shoes. Refer to "HUBS AND BEARINGS"...
Page 171 Sec. 5A G M C S E R V I C E M A N U A L Page 164 HYDRAULIC BRAKES Type "FR-3" (Fig. 3) When the brakes are released, the pull-back 1. Jack up vehicle until wheels are clear of springs return the shoes to the rest position.
Page 172: Bleeding Brakes
Sec. 5A G M C S E R V I C E M A N U A L Page 165 HYDRAULIC BRAKES remove the cover from the access hole and insert the lever away from the star wheel. Using a brake a screwdriver.
Page 173 ______________________ G M C S E R V I C E M A N U A L P age^166 HYDRAULIC BRAKES F R O N T — F R O N T — T \ DASH MOUNTED CYLINDER DUO SERVO TW IN-ACTIO N DUO-SERVO TW IN-ACTIO N...
Page 174: Brake Pedal And Linkage
Sec. 5A G M C S E R V I C E M A N U A L Page 167 HYDRAULIC BRAKES cap or cover opening. Bleed air from hose before SPLIT SYSTEM ("S" MODELS) tightening connection. Open valves at both ends of The split system on "S"...
Page 175 G M C S E R V I C E M A N U A L Page 168_______________________ HYDRAULIC BRAKES 3 11 1 Clutch Pedal 8 Pedal Return Spring Shaft Lever 9 Pedal Support Bracket 2 Clamp Bolt and Nut Pedal Bumper 3 Bushings Spring Washer...
Page 176: Master Cylinders
Sec. 5A G M C S E R V I C E M A N U A L Page 169 HYDRAULIC BRAKES 1 Pedal Upper Half 9 Pedal to Push Rod Bolt 2 Pedal Upper and Lower 10 Clevis Seals 11 Adjusting Nut 3 Upper to Lower Pedal 12 Push Rod...
Page 177 Sec. 5A G M C S E R V I C E M A N U A L Page 170 HYDRAULIC BRAKES 3. Pull back boot on push rod. Visually check 3. Tighten lock nut. to see if piston is seated firmly against piston snap 4.
Page 178 Sec. 5A G M C S E R V I C E M A N U A L Page 171 HYDRAULIC BRAKES B y-pass ports may be obstructed by one of the fol inder to dash (nuts are welded to inner side of dash) and remove master cylinder assembly.
Page 179 Sec. 5A G M C S E R V I C E M A N U A L Page 172 HYDRAULIC BRAKES 1 R eservoir Cover 2 M aster Cylinder Housing 3 Piston Return Spring 4 Primary Cup 5 Piston Assem bly 6 Snap Ring 7 Boot 8 Check Valve (Brake Cylinder Only)
Page 180 Sec. 5A G M C S E R V I C E M A N U A L Page 173 HYDRAULIC BRAKES 1. Examine cylinder bores. If scored or rust 7. If necessary, adjust the brake pedal free- play as directed. ed, recondition by honing.
Page 181 Sec. 5A G M C S E R V I C E M A N U A L Page 174 HYDRAULIC BRAKES 1 Primary Piston Seal Cup 10 Tube Seat 16 Stop Bolt 2 Primary Piston 11 Secondary Piston Return 17 Primary Return Spring 3 Cover Seal Spring...
Page 182: Wheel Cylinders
Sec. 5A G M C S E R V I C E M A N U A L Page 175 HYDRAULIC BRAKES BRAKE PIPE DISTRIBUTION A N D SWITCH ASSEMBLY All models with split brake system are equip INSTALLATION 1. Make sure new switch is clean and free of ped with a brake pipe distribution and switch a s...
Page 183 Sec. 5A G M C S E R V I C E M A N U A L Page 176 HYDRAULIC BRAKES and remove bolt attaching connecting tube fitting TYPE "FR-3" AND "FR-3A" to lower cylinder. Remove connecting tube and fitting assembly.
Page 184 Sec. 5A G M C S E R V I C E M A N U A L Page 177 HYDRAULIC BRAKES TYPE “ F” A N D TYPE “ F A ” - F R O N T Figure 15— Checking Fit of Piston in Wheel Cylinder parts to be replaced when overhauling wheel cyl...
Page 185 1. Repair kits are available which contain the parts to be replaced when overhauling wheel cyl IMPORTANT: Only genuine GMC parts should inders. Refer to Parts Book for repair kit part be used. Non-genuine parts may deteriorate and numbers.
Page 186: Hydraulic Lines
Sec. 5A G M C S E R V I C E M A N U A L Page 179 HYDRAULIC BRAKES spring out of cylinder. Remove cups from pistons. Remove bleeder valve from upper cylinder. Inspection and Repair 1. Repair kits are available which contain the parts to be replaced when overhauling wheel cyl...
Page 187: Vacu Um Power Cylinders
Sec. 5A G M C S E R V I C E M A N U A L Page 180 HYDRAULIC BRAKES VACU UM POWER CYLINDERS is operating, pedal will tend to fall away under foot Vacuum power cylinders are used as standard equipment or are available as optional equipment pressure when engine starts, and le ss pressure on all vehicles with hydraulic brakes covered by...
Page 188 Sec. 5A G M C S E R V I C E M A N U A L Page 181 HYDRAULIC BRAKES Conventional - behind cab step, immediately below left-hand door. Vacuum reserve tank is lo cated in this same area, when used. See figure 19. Tilt Cab - between frame side rails in front of the radiator and behind the front bumper.
Page 189 Sec. 5A G M C S E R V I C E M A N U A L Page 182 HYDRAULIC BRAKES element type filter and cleaning is NOT recom mended. When cleaner becomes so laden with dirt, that tapping it against some solid surface (such as a work bench) will not remove foreign matter, then a new cleaner should be installed.
Page 190: Vacuum Check Valve
gec 5A . G M C S E R V I C E M A N U A L ______________________ Page‘i83 HYDRAULIC BRAKES V ACU U M CHECK VALVE On all vehicles with vacuum power assisted Removal and installation of valves on P4500, hydraulic brakes a check valve is used somewhere "S"...
Page 191: Vacuum Reserve Tank
Sec. 5A G M C S E R V I C E M A N U A L Page 184 HYDRAULIC BRAKES V A CU U M RESERVE TANK A vacuum reserve tank is used as standard hind the cab step. equipment on "S”...
Page 192 Sec. 5A G M C S E R V I C E M A N U A L Page 185 HYDRAULIC BRAKES least 26 inches of mercury vacuum. Let the engine idle. The pump should maintain at least 20 inches of mercury vacuum with the engine idling.
Page 193 Sec. 5A G M C S E R V I C E M A N U A L Page 186 HYDRAULIC BRAKES tube directed downward to prevent the entrance of dirt or water into the power cylinder. The hydraulic input line from the master cyl inder is attached to the fluid inlet port located in the control valve.
Page 194: Air Power Cylinder
Sec. 5A G M C S E R V I C E M A N U A L Page 187 HYDRAULIC BRAKES bubbles indicates a leaking control valve poppet sary), repeat test described in paragraph 2 above. air inlet seal. If pressure is still too low or if pressure drops, 4.
Page 195 Sec. 5A G M C S E R V I C E M A N U A L Page 188 HYDRAULIC BRAKES 3. Check backing plate attaching bolts to make 6 Brake Shoe Adjusting 1 Wheel Cylinder sure they are tight. Clean all dirt off backing plate. 2 Brake Shoe Return 4.
Page 196 Sec. 5A G M C S E R V I C E M A N U A L Page 189 HYDRAULIC BRAKES 12 A djusting Socket 1 Shoe Guide Plate 2 Anchor Pin 13 Actuating L ev er 3 Wheel C ylinder 14 L ever Return Spring Figure 2 8 —...
Page 197 Sec. 5A G M C S E R V I C E M A N U A L Page 190 HYDRAULIC BRAKES Figure 3 0 — Installing Primary Shoe Return Spring from brake shoe contact surfaces on backing plate using fine emery cloth. 4.
Page 198 Sec. 5A G M C S E R V I C E M A N U A L Page 191 HYDRAULIC BRAKES CAUTION: DO NOT hook the actuating link over the anchor pin with a regular spring hook tool. This may damage the wheel cylinder boot.
Page 199 ______________________ G M C S E R V I C E M A N U A L Page 192 HYDRAULIC BRAKES Connector Tube Spring Washer Bolt Flat Washer Backing Plate Bleeder Valve Wheel Cylinder 14 Contact Plug Brake Shoe 15 W edge Spring 16 Torsion Spring Flat Washer Anti-rattle...
Page 200 Sec. 5A G M C S E R V I C E M A N U A L Page 193 HYDRAULIC BRAKES plug. This can be done with a file, taking care to not create a "flat spot" on the lining. (An alternate method is to block adjuster lever in extended posi...
Page 201 Sec. 5A G M C S E R V I C E M A N U A L Page 194 HYDRAULIC BRAKES 2. Install brake shoes with cut-away end of cracked, or weakened, replace with new springs. shoe web next to adjusting screw and with ends of 5.
Page 202 Sec. 5A G M C S E R V I C E M A N U A L Page 195 HYDRAULIC BRAKES T-2726 Figure 3 8 — Removing Brake Shoe Hold D ow n Pins 5. Remove the brake shoe hold-down springs and pins by compressing the spring with Tool (J- 22348) and, at the same time, pushing the pin back through the flange plate toward the tool.
Page 203 Sec. 5A G M C S E R V I C E M A N U A L Page 196 HYDRAULIC BRAKES Figure 4 0 — M ea surin g Points for Brake Shoe Centering 6. Install cup, spring, and retainer on end of hold-down pin.
Page 204 Sec. 5A G M C S E R V I C E M A N U A L Page 197 HYDRAULIC BRAKES TYPE “FR -3A ” REAR BRAKE The type "FR-3A" rear brake is the same as the type "FR-3" brake except for method of ad justment.
Page 205 Sec. 5A G M C S E R V I C E M A N U A L Page 198 HYDRAULIC BRAKES 20 Lock Wire 2 Brake Lining 11 Bleeder Valve 3 Brake Shoe 12 Wheel Cylinder Cover 21 Shoe Return Spring (Long) 4 Hole Cover 13 Wheel Cylinder 22 Crank Link (Long)
Page 206: Brake Shoe Relining
Sec. 5A G M C S E R V I C E M A N U A L Page 199 HYDRAULIC BRAKES 4. Install the other brake shoe in same man INITIAL MANUAL LINING ADJUSTMENT ner as described in paragraphs 2 and 3. 1.
Page 207 Sec. 5A G M C S E R V I C E M A N U A L Page 200 HYDRAULIC BRAKES TROUBLESHOOTING CHART LOW PEDAL OR PEDAL GOES TO TOE BOARD PROBABLE CAUSE REMEDY E xcessive clearance between linings and drum. Adjust brakes.
Page 208 Sec. 5A G M C S E R V I C E M A N U A L Page 201 HYDRAULIC BRAKES LIGHT PEDAL PRESSURE - - BRAKES TOO SEVERE PROBABLE CAUSE REMEDY 1. Brake adjustment not correct. 1. Adjust the brakes. 2.
Page 209 Sec. 5A G M C S E R V I C E M A N U A L Page 202 HYDRAULIC BRAKES ALL BRAKES DRAG WHEN ADJUSTMENT IS KNOWN TO BE CORRECT (Cont'd.) PROBABLE CAUSE REMEDY 2. Improper fluid. 2. Replace rubber parts and fill with recom mended brake fluid.
Page 210 Sec. 5A G M C S E R V I C E M A N U A L Page 203 HYDRAULIC BRAKES PULLS TO ONE SIDE (Cont’d.) PROBABLE CAUSE REMEDY 10. Brake dragging. 10. Check for loose lining. Adjust. 11. Weak ch assis springs, loose U-bolts, loose 11.
Page 211 Sec. 5A G M C S E R V I C E M A N U A L Page 204 HYDRAULIC BRAKES BRAKES CHATTER PROBABLE CAUSE REMEDY 1. Incorrect lining to drum clearance. 1. Readjust to recommended clearances. 2. Loose backing plate. 2.
Page 212 Sec. 5A G M C S E R V I C E M A N U A L Page 205 HYDRAULIC BRAKES NO BOOST — HARD PEDAL REMEDY PROBABLE CAUSE Bent, broken obstructed tube. Collapsed hose. Replace defective parts. 2. Replace valve. 2.
Page 213 Sec. 5A G M C S E R V I C E M A N U A L Page 206 HYDRAULIC BRAKES SPECIFICATIONS FRONT BRAKES TRUCK SERIES 4500 L4000 SG500 5500 E6500 T y p e ..............Duo-Servo “ F " “...
Page 214 Sec. 5A G M C S E R V I C E M A N U A L Page 207 HYDRAULIC BRAKES SPECIFICATIONS (CONT.) VACUUM PUMP SPECIFICATIONS Model (exc. D LV 4000)................4GA Model (D LV 4 0 00 ) ..................4GB Rotation...................
Page 215 Sec. 5B G M C S E R V I C E M A N U A L Page 208 SECTION 5B Ait Q n& k& i INDEX Subject Page No. Subject Page No. Brake System Equipment ........208 Trailer Emergency Air Supply Control Valves 222 Brake System Maintenance ........
Page 216 Sec. 5B G M C S E R V I C E M A N U A L Page 209 AIR BRAKES C O N S T A N T PRESSURE LIN ES D ELIVERY LINES 16 Trailer Brake Emergency 8 Trailer Brake Hand 1 Slack Adjuster Control Valve...
Page 217 Sec. 5B G M C S E R V I C E M A N U A L Page 210 AIR BRAKES 6 Brake Pedal 1 Application Valve 7 Push Rod End 2 Valve Mounting Bracket 8 Adjusting Nut 3 Pedal Support Bracket 4 Pedal Return Spring 9 Push Rod 5 Pedal Stop Bumper...
Page 218 Sec. 5B G M C S E R V I C E M A N U A L Page 211 AIR BRAKES 1 Line to Air Gauge 4 Double Check Valve 2 Valve Mounting Bolt and Stop Light Switch and Nut (in Engine 5 Line to Tractor Compartment) Protection Valve...
Page 219 Sec. 5B G M C S E R V I C E M A N U A L Page 212 AIR BRAKES 4. Depress and hold brake pedal in full-down position. 5. Turn adjusting bolt and stop plate assembly up until plate contacts brake pedal, with pedal in full-down position.
Page 220 Sec. 5B G M C S E R V I C E M A N U A L Page 213 AIR BRAKES 1 Air Brake Hose Snap Ring 2 Brake Chamber 7 Brake Camshaft 1 Adjusting Worm Shaft 7 Brake Chamber 3 Mounting Bracket Lubrication Hole Plug 2 Lubrication Hole Plug...
Page 221 Sec. 5B G M C S E R V I C E M A N U A L Page 214 AIR BRAKES equally spaced holes near clamping flange in non after being adjusted, this angle should still be pressure plate provide for breathing and drainage. greater than 90 degrees;...
Page 222 Sec. 5B G M C S E R V I C E M A N U A L Page 215 AIR BRAKES bolts should be checked for looseness at regular DIVIDED TANK CHECK VALVE SERVICE intervals and tightened if necessary. Air tank may (Refer to Fig.
Page 223 Sec. 5B G M C S E R V I C E M A N U A L Page 216 AIR BRAKES Installation 1. Install valve in delivery port of application valve (or air tank line). 2. Connect air lines to valve. 3.
Page 224 Sec. 5B G M C S E R V I C E M A N U A L Page 217 AIR BRAKES which lifts plunger, moving inlet valve off seat. REPLACEMENT (Refer to Fig. 13) This perm its flow of air from wet tank into column Removal section of valve.
Page 225 Sec. 5B G M C S E R V I C E M A N U A L Page 218 AIR BRAKES "COWL” MODELS 2. To install pedal, valve and support bracket as an assembly, position in cab and attach assem bly to cab with bolts.
Page 226 Sec. 5B G M C S E R V I C E M A N U A L Page 219 AIR BRAKES test is probably caused by worn or deteriorated and the push rod to pedal pin with engine oil. Use oil sparingly.
Page 227 Sec. 5B G M C S E R V I C E M A N U A L Page 220 AIR BRAKES Figure 14 — Trailer Hose Coupling foot brake system or by the trailer brake hand control valve. Flexible hoses are used to make the connection between the truck and the trailer.
Page 228 Sec. 5B G M C S E R V I C E M A N U A L Page 221 AIR BRAKES gauge should be checked regularly with an accurate the manufacturer and is not reparable. Switch has test gauge. If pressure reading varies 4 pounds or only one wire terminal, being internally grounded.
Page 229 Sec. 5B G M C S E R V I C E M A N U A L Page 222 AIR BRAKES PUSH TO SUPPLY TRAILER AIR PULL FOR EMERGENCY T- 29 70 Figure 17— Emergency Control Valve Decal There are two different model control valves used on these vehicles but both operate on the same principle.
Page 230 Sec. 5B G M C S E R V I C E M A N U A L Page 223 AIR BRAKES Installation SERVICEABILITY TESTS 1. Position valve at mounting bracket (tilt cab) or cowl (conventional) and attach air lines. Operating Tests 2.
Page 231 Sec. 5B G M C S E R V I C E M A N U A L Page 224 AIR BRAKES at hand control valve exhaust port, using soap holes in the valve guide into the trailer brake suds. service line.
Page 232 Sec. 5B G M C S E R V I C E M A N U A L Page 225 AIR BRAKES L im itin g— Q uick Release V a lv e E xh au st Port Inlet V a lv e P lu nger V a lv e Carrier...
Page 233 Sec. 5B G M C S E R V I C E M A N U A L Page 226 AIR BRAKES Installation brakes applied, coat the exhaust ports of the two- 1. Position valve in instrument panel or on way valve and limiting quick release valve with fire wall and connect air lines.
Page 234 Sec. 5B G M C S E R V I C E M A N U A L Page 227 AIR BRAKES CONTROL PORT INLET VALVE SEAT m | | RESERVOIR EXHAUST VALVE j ATMOSPHERIC PUSH-PULL VALVE INLET EXHAUST PORT VALVE SUPPLY PORT...
Page 235 Sec. 5B G M C S E R V I C E M A N U A L Page 228 AIR BRAKES control valve and the open exhaust port of the foot a normal service brake application is made, air control valve.
Page 236 Sec. 5B G M C S E R V I C E M A N U A L Page 229 AIR BRAKES PREVENTIVE MAINTENANCE Make and hold a service brake application and again check the actuator drain slot for service DD3 BRAKE ACTUATOR diaphragm leakage.
Page 237 Sec. 5B G M C S E R V I C E M A N U A L Page 230 AIR BRAKES is closed. On initial build-up, as air enters the NOTE OF CAUTION: Air will be ex parking reservoir to which the inversion valve hausted out the line that was connected to supply port is connected, it will pass by the open the parking port, if the push-pull control...
Page 238 Sec. 5B G M C S E R V I C E M A N U A L Page 231 AIR BRAKES complete the release of the brakes. A full 100 psi service brake application after the push-pull con trol valve is pushed in should complete the release. LEAKAGE Start leakage checks with system pressure up to governor cut-out and brakes released.
Page 239 Sec. 5B G M C S E R V I C E M A N U A L Page 232 AIR BRAKES application will be necessary to complete release On tractors which have an air operated em er of tractor brakes. gency brake system (such as DD3), as opposed to Leakage Test.
Page 240 Sec. 5B G M C S E R V I C E M A N U A L Page 233 AIR BRAKES 3. Open air tank drain valves and exhaust In the event of an automatic emergency ap pressure from brake system . plication (loss of air pressure) and it is necessary to move the vehicle before air pressure can be 4.
Page 241 Sec. 5B G M C S E R V I C E M A N U A L Page 234 AIR BRAKES 11 Brake Shoe Return Spring 6 Camshaft and Brake 1 Lock Ring 12 Guide Pin Washer Chamber Bracket 2 Spacer 13 Guide Pin "C"...
Page 242 Sec. 5B G M C S E R V I C E M A N U A L Page 235 AIR BRAKES Section A - A Looking in Direction of A rrow s 1 Brake Shoe 2 Brake Shoe Return Spring 3 Cam (integral with shaft)
Page 243 Sec. 5B G M C S E R V I C E M A N U A L Page 236 AIR BRAKES CAMSHAFT CAUTION: Do not overlubricate camshaft, as excess lubricant may be forced by the seals into Rear brake camshafts have constant lift, S- the brake drums.
Page 244 Sec. 5B G M C S E R V I C E M A N U A L Page 237 AIR BRAKES AUTOMATIC ADJUSTER 1 Adjusting Bolt and Shoe Retainer Assembly All Stopmaster brakes have automatic adjust er mechanisms. The basic part of the adjuster (refer to fig.
Page 245 Sec. 5B G M C S E R V I C E M A N U A L Page 238 AIR BRAKES linear advance or rate of adjustment. adjuster assembly installed. When the plunger a s Procedures covering the removal and install sembly is moved outward to apply the shoe against ation of automatic adjuster components are given the drum, the plunger guide will slide across the...
Page 246 Sec. 5B G M C S E R V I C E M A N U A L Page 239 AIR BRAKES Figure 31 — Standard Stopmaster Air Cham ber Components regardless of which direction adjusting bolt is 5. Remove bolt and nut which secure clamp turned.
Page 247 Sec. 5B G M C S E R V I C E M A N U A L Page 240 AIR BRAKES to shoe with correct size rivets, and rivets must be properly upset. Maximum braking efficiency can be obtained immediately if linings are trued- up with a lining grinder so they are properly cen...
Page 248 Sec. 5B G M C S E R V I C E M A N U A L Page 241 AIR BRAKES 1 Brake Shoe and Lining Assembly 2 Adjusting Bolt Assy. 3 Adjusting Sleeve (Actuator) Plunger Seal and Retainer Adjusting Plunger Brake Spider (Plunger Housing)
Page 249 Sec. 5B G M C S E R V I C E M A N U A L Page 242 AIR BRAKES PL U N G E R 1 Retaining Cage 5 Wedge Return Spring 2 "Ears" on Washer Return Spring Washer 3 Roller 7 Cotter Pin 4 Wedge Retainer...
Page 250 Sec. 5B G M C S E R V I C E M A N U A L Page 243 AIR BRAKES IN STALLIN G TO O L A N C H O R PLUNGER PLUNGER SEAL T-2339 T-2340 Figure 3 6 — Installing Anchor Plunger and Seal under "Brake Shoe Installation"...
Page 251 Sec. 5B G M C S E R V I C E M A N U A L Page 244________________________ AIR BRAKES “FAIL-SAFE” BRAKES GENERAL through the mechanical actuating components as described later. The Stopmaster "Fail-Safe" is a mechanical The outer chamber contains a spring-loaded actuation feature for power brakes and is two-fold piston which acts against the service brake cham...
Page 252 Sec. 5B G M C S E R V I C E M A N U A L Page 245 AIR BRAKES 9 W asher 1 Spanner Nut Retaining W asher 17 Housing to Plunger "O" Ring 2 Spanner Nut 10 Bolt 18 Air Chamber Piston Plunger 11 N on-P ressu re Housing...
Page 253 Sec. 5B G M C S E R V I C E M A N U A L Page 246 AIR BRAKES Figure 4 3 — Removing “Fail-Safe” Assem bly NOTE: Do not tighten vise jaws enough to d is tort pressure from cap assembly.
Page 254 Sec. 5B G M C S E R V I C E M A N U A L Page 247 AIR BRAKES Figure 4 4 — Rem oving Pressure Housing with “Strap” Wrench year periods, whichever occurs first (also depend plate rod and install new boot on plate rod.
Page 255 Sec. 5B G M C S E R V I C E M A N U A L Page 248 AIR BRAKES . Connect all air lines and build up air p res or by putting pressure housing in vise and using sure in system to normal operating pressure.
Page 256 Sec. 5B G M C S E R V I C E M A N U A L Page 249 AIR BRAKES GENERAL TROUBLESHOOTING CHART NO BRAKES PROBABLE CAUSE REMEDY 1. No air pressure 1. Check for leaks, broken lines, etc. Repair or replace as necessary 2.
Page 257 Sec. 5B G M C S E R V I C E M A N U A L Page 250 AIR BRAKES SLOW BRAKE RELEASE PROBABLE CAUSE REMEDY 1. Linkage binding 1. Lubricate linkage 2. Restriction in line . Remove restriction or replace line. 3.
Page 258 Sec. 5B G M C S E R V I C E M A N U A L Page 251 AIR BRAKES AIR PRESSURE ABOVE NORMAL PROBABLE CAUSE REMEDY 1. Defective air gauge . Replace 2. Governor out of adjustment or defective .
Page 259 Sec. 5B G M C S E R V I C E M A N U A L Page 252 AIR BRAKES STOPMASTER TROUBLESHOOTING CHART "FAIL-SAFE" PARKING BRAKE WILL NOT RELEASE REMEDY PROBABLE CAUSE 1. Air leak in "Fail-Safe" lines .
Page 260 Sec. 5B G M C S E R V I C E M A N U A L Page 253 AIR BRAKES SERVICE BRAKES INOPERATIVE PROBABLE CAUSE REMEDY 1. Low air pressure . Check system for leaks 2. Faulty brake chamber diaphragm .
Page 261 Sec. 5C G M C S E R V I C E M A N U A L Page 254 SECTION 5C PanJiinxj, Rtovkel EXTERNAL CONTRACTING BAND TYPE BRAKE rear off brake drum and anchor bar (fig. ), re External contracting band type parking brake moving band and lining assembly off over propeller is mounted at rear of transm ission (fig.
Page 262 Sec. 5C G M C S E R V I C E M A N U A L Page 254A PARKING BRAKES anchor bracket is placed over anchor bar. lock washers, and bolts attaching propeller shaft 2. Install anchor screw through bracket and center bearing hanger bracket to crossmember.
Page 263 Sec. 5C G M C S E R V I C E M A N U A L Page 254B PARKING BRAKES Adjust lining to drum clearance as previ ously directed under "Brake Adjustment.” BRAKE DRUM REMOVAL 1. Remove brake shoes as previously directed under "Brake Shoe Removal.”...
Page 264 Sec. 5C G M C S E R V I C E M A N U A L Page 254C PARKING BRAKES 3. Install cable assembly from back of back ing plate. Push retainer through hole in backing plate until tangs securely grip inner side of plate. 4.
Page 265 Sec. 5C G M C S E R V I C E M A N U A L Page 254D PARKING BRAKES OPTIONAL AIR-OPERATED PARKING BRAKES Safe." For information concerning these features Models in this manual using air brake system s refer to "AIR BRAKES"...
Page 266 ..............In-Vehicle Service Operations (In-Line Engine) ...... In-Vehicle Service Operations (V6 Engines) ......Trouble Diagnosis Chart ..............Torque Wrench Specifications ............ENGINE APPLICATION CHART GMC ENGINE GMC ENGINE TRUCK SERIES STANDARD OPT. STANDARD OPT. TRUCK SERIES LA, LV4000 305C 351C...
Page 267 Sec. 6A G M C S E R V I C E M A N U A L Page 256 GASOLINE ENGINES 5 Oil From Camshaft 1 To Timing Chain Rear Bearing and Sprocket 6 Oil Galleries 2 Oil From Camshaft 7 Oil Drain-Back Holes Front Bearing 8 Oil Filter...
Page 268 Sec. 6A G M C S E R V I C E M A N U A L Page 257 GASOLINE ENGINES again. The upper mark on dipstick is "FULL,” the lower "ADD" or "ADD OIL." Keep level as close as possible to "FULL"...
Page 269 Sec. 6A G M C S E R V I C E M A N U A L Page 258 GASOLINE ENGINES remove the housing assembly. 2. Remove the filter element from the housing, then with suitable drift, drive the valve assembly out of housing as shown in figure 4.
Page 270: Cylinder Compression Test
Sec. 6A G M C S E R V I C E M A N U A L Page 259 GASOLINE ENGINES Stop engine, disconnect plug wires and re move spark plugs and gaskets. CYLINDER COMPRESSION TEST With carburetor choke and throttle in wide- open position, operate starter with remote control switch.
Page 271: Battery And Battery Cable Service
Sec. 6A G M C S E R V I C E M A N U A L Page 260 GASOLINE ENGINES are numbered consecutively from front to rear and firing order is 1 -5 -3 -6 -2 -4 (fig. 8). Refer to ENGINE ELECTRICAL (SEC.
Page 272: Idle Speed And Mixture
Sec. 6A G M C S E R V I C E M A N U A L Page 261 GASOLINE ENGINES 4. While observing vacuum gauge and tach ometer, set engine idle speed and adjust carbur etor idle mixture screw s to provide steady running engine.
Page 273: Valve Lash A D Ju Stm E N Ts
Sec. 6A G M C S E R V I C E M A N U A L Page 262 GASOLINE ENGINES Figure 13— Cylinder H ead Bolt Tightening Sequence for In-Line Engine Figure 15— Cylinder Head Bolt Tightening Sequence on V6 Engine 2.
Page 274 Sec. 6A G M C S E R V I C E M A N U A L Page 263 GASOLINE ENGINES CYLINDER HEAD BOLT TORQUE A N D VALVE LASH ADJUSTMENT (V6 ENGINE) A check of cylinder head bolt torque should be made at regular tune-up intervals on V6 engines, and should be followed by valve lash adjustment.
Page 275 Sec. 6A G M C S E R V I C E M A N U A L Page 264 GASOLINE ENGINES SPECIFICATIONS IN -LIN E ENGINE TUNE-UP CHART Except as otherwise indicated, the following specifications apply to both engine models. FIR IN G O R D ER .................1-5-3-6-2-4 EN GIN E T Y P E AND NUM BER OF C Y L IN D E R S ..........
Page 276 Sec. 6A G M C S E R V I C E M A N U A L Page 265 GASOLINE ENGINES Zncjine Replacem ent GENERAL into place in chassis. Install support crossmember and install engine mountings. Refer to ENGINE Two types of engines, namely "In-line"...
Page 277 Sec. 6A G M C S E R V I C E M A N U A L Page 266 GASOLINE ENGINES INSTALLATION disengage transm ission drive gear from clutch 1. Use crane-type hoist to move engine into driven member splines. When free from transm is position in chassis.
Page 278 Sec. 6A G M C S E R V I C E M A N U A L Page 267 GASOLINE ENGINES 10. Disconnect cooling system and heater INSTALLATION hoses. Assem ble clutch components andtransmission 11. Disconnect propeller shaft from trans to engine referring to applicable instructions in m ission.
Page 279 Sec. 6A G M C S E R V I C E M A N U A L Page 268 GASOLINE ENGINES VALVE MECHANISM REPLACEMENT REMOVAL 1. Remove rocker arm cover as previously directed. 2. Remove rocker arm nuts, rocker arm balls, rocker arms and push rods.
Page 280 Sec. 6A G M C S E R V I C E M A N U A L Page 269 GASOLINE ENGINES garden hose approximately four feet in length. Place one end of the hose near the end of each in take and exhaust valve with the other end of the hose to the ear.
Page 281 Sec. 6A G M C S E R V I C E M A N U A L Page 270 GASOLINE ENGINES 1. Place the gasket in position over the dowel groove of the stem, making sure the seal is flat and not twisted.
Page 282 Sec. 6A G M C S E R V I C E M A N U A L Page 271 GASOLINE ENGINES APPLY SEALANT TO SHADED AREAS ONLY Figure 2 3 — Sealer on Bearing Cap Area on Cylinder Block Figure 2 2 —...
Page 283 Sec. 6A G M C S E R V I C E M A N U A L Page 272 GASOLINE ENGINES Figure 2 4 — Rem oving Crankshaft Dam per INSTALLER T O O L 1. Coat front seal contact area (on damper Figure 2 6 —...
Page 284 Sec. 6A G M C S E R V I C E M A N U A L Page 273 GASOLINE ENGINES Figure 2 7 — Centering Tool in Engine Cover damper installation will not damage seal and to position seal to seat evenly around the damper or hub surface.
Page 285 Sec. 6A G M C S E R V I C E M A N U A L Page 274 GASOLINE ENGINES correct hole alignment and dowel pin fit. Dowel out and remove the three flywheel-to-crankshaft dowel pinSo Crankshaft must be turned each time a pins must be driven into place as they are inter...
Page 286 Sec. 6A G M C S E R V I C E M A N U A L Page 275 GASOLINE ENGINES C rankcase Ventilation V a lv e FRONT 7 W JK - ' / 1 End Bracket 6 Rocker Arm Shaft 10 Exhaust Manifold 2 Adjusting Screw 7 Spring...
Page 287 Sec. 6A G M C S E R V I C E M A N U A L Page 276 GASOLINE ENGINES against valve spring cap meanwhile striking spring cap lightly with hammer to unseat the valve locking keys. Continue to turn the stud nut until spring is compressed sufficiently to permit removal of the two valve keys.
Page 288 Sec. 6A G M C S E R V I C E M A N U A L Page 277 GASOLINE ENGINES 1. Drain cooling system . C ylinder H e a d 2. Disconnect exhaust pipe from exhaust mani fold, then remove exhaust manifold and gasket.
Page 289 ______________________ G M C S E R V I C E M A N U A L Page^278 GASOLINE ENGINES Engine Front Cover Crankshaft Gear or Sprocket Oil Slinger Oil Seal Assy. Crankshaft Installer Screw Installer Nut Thrust Bearing Pu lley i In sta lle rl Thrust 1 Pulley Installer...
Page 290 Sec. 6A G M C S E R V I C E M A N U A L Page 279 GASOLINE ENGINES 1 Suction Tube and 5 Cylinder Block Screen Assy. 6 Pump Drive Shaft 2 Bracket Bolt 7 Pump to Block Bolts (20-25 ft.-lbs.) (30-35 ft.-lbs.) 8 Oil Pump...
Page 291 Sec. 6A G M C S E R V I C E M A N U A L Page 280 GASOLINE ENGINES TACHOMETER DRIVE ADAPTER REPLACEMENT REMOVAL (Fig. 41) 1. Remove floor pan from cab on conventional cab models, or remove shield from cab rear sup port on tilt cab models.
Page 292 Sec. 6A G M C S E R V I C E M A N U A L Page 281 GASOLINE ENGINES Figure 4 4 — Timing M arks on V6 Engine (Typical) Run engine at full throttle (no-load) momentarily and check engine speed on tachometer and note p ressure on gauge in line.
Page 293 Sec. 6A G M C S E R V I C E M A N U A L Page 282 GASOLINE ENGINES TORQUE WRENCH SPECIFICATIONS (IN-LINE ENGINES) Item Ft. Lbs. Cylinder Head Bolts ................Manifold Clamps (O uter)................Manifold Clamps (Except Outer) ............
Page 294 Sec. 6A G M C S E R V I C E M A N U A L Page 283 GASOLINE ENGINES < l'iauble ^biaano.lli Gbant ..— ------- - - ----- —-- ■ ■ ..■ ..HARD STARTING SYMPTOM A - SLOW CRANKING POSSIBLE CAUSES REMEDY...
Page 295 Sec. 6A G M C S E R V I C E M A N U A L Page 284 GASOLINE ENGINES HARD STARTING (CONT.) SYMPTOM D - IGNITION TROUBLES (Cont’d.) POSSIBLE CAUSES REMEDY 6. Test coil and condenser; replace if necessary. 6.* Defective ignition coil or condenser.
Page 296 Sec. 6A G M C S E R V I C E M A N U A L Page 285 GASOLINE ENGINES LACK OF POWER (CONT.) SYMPTOM D - FAULTY ACCELERATION POSSIBLE CAUSES REMEDY 1. Defective carburetor (accelerator pump - clogged jets).
Page 297 Sec. 6A G M C S E R V I C E M A N U A L Page 286 GASO LINE ENGINES ROUGH IDLE A N D /O R STALLING (CONT.) SYMPTOM A - ERRATIC RUNNING OR SURGING (Cont'd.) POSSIBLE CAUSES REMEDY 4.
Page 298 Sec. 6A G M C S E R V I C E M A N U A L Page 287 GASOLINE ENGINES LOW ENGINE OIL PRESSURE (When checked with engine at normal operating temperature) POSSIBLE CAUSES REMEDY 1. Defective oil gauge or sending unit. 1.
Page 299 Sec. 6A _____ ________ G M C S E R V I C E M A N U A L Page 288 GASOLINE ENGINES Inspect engine front and rear mountings as part of regular engine maintenance program. Be sure all bracket attaching bolts are kept tight. Refer to ENGINE MOUNTINGS (SEC.
Page 300 Since the equipment used with various truck models APPLICATION CHART is somewhat varied, reference must be made to applicable maintenance paragraphs in this manual TRUCK SERIES GMC ENGINE for service instructions for servicing air cleaners, DLV. DLA 4000 DH478 fuel filters, and crankcase ventilation system . In...
Page 301 Sec. 6B G M C S E R V I C E M A N U A L Page 290 TORO-FLOW DIESEL ENGINE FUEL SYSTEM Make periodic inspection of fuel filters, lines, and injection units for evidence of leaks and dam age.
Page 302 Sec. 6B G M C S E R V I C E M A N U A L Page 291 TORO-FLOW DIESEL ENGINE 1 Fuel Leak-off Hose 5 Adapter 9 Overflow Valve 2 Injection Nozzle Bolts 6 Fuel Injection Pump 10 Fuel Receptacle and Lock Washers Assembly...
Page 303 Sec. 6B G M C S E R V I C E M A N U A L Page 292 TORO-FLOW DIESEL ENGINE 4. In cases where loose, corroded, or other Before installing a fuel injection nozzle, use fine w ise defective battery cables and/or wiring are brass-bristled brush (fig.
Page 304 Sec. 6B G M C S E R V I C E M A N U A L Page 293 TORO-FLOW DIESEL ENGINE 2. Referring to ENGINE FUEL SYSTEM (SEC. 6M) in this manual, service air cleaners and fuel filters. Also, check operation of accelerator con trol linkage for free movement.
Page 305 Sec. 6B G M C S E R V I C E M A N U A L Page 294 TORO-FLOW DIESEL ENGINE DH478 TORO-FLOW DIESEL ENGINE TUNE-UP CHART ENGINE MODEL ........... DH478 FUEL INJECTION CYLINDER COMPRESSION (PSI) . . . 500 (Min.)* TIMING ......."INJ”...
Page 306 Sec. 6B G M C S E R V I C E M A N U A L Page 295 TORO-FLOW DIESEL ENGINE 12. Fill cooling system and connect battery remove front and rear mounting bolts. 15. Lift power plant out of chassis, using care cables.
Page 307 Sec. 6B G M C S E R V I C E M A N U A L Page 296 TORO-FLOW DIESEL ENGINE 5. Referring to figure 7 assem ble rotator (if removed), inner and outer springs, and spring cap, then use compressor tool to force springs and cap down far enough to permit installation of valve keys.
Page 308 Sec. 6B G M C S E R V I C E M A N U A L Page 297 TORO-FLOW DIESEL ENGINE 1 Manifold Clamp 5 Cylinder Head 8 Exhaust Manifold 2 Intake Manifold 6 Manifold End Bolt 9 Tube Clamp and Bracket 3 Oil Level Dipstick 7 Plain Washer and Lock 10 Dipstick Tube...
Page 309 Sec. 6B G M C S E R V I C E M A N U A L Page 298 TORO-FLOW DIESEL ENGINE 1 End B racket 4 Spacer 7 A djusting S crew 2 B racket Bolt and Plain W asher 5 Spring S p ecia l Bolt 3 R ock er A rm...
Page 310 Sec. 6B G M C S E R V I C E M A N U A L Page 299 TORO-FLOW DIESEL ENGINE DAMPER CENTER PLUG PULLER SCREW Figure 11 — Tool Application for Rem oving Crankshaft Dam per Thrust Bearing 1 Seal "O"...
Page 311 Sec. 6B G M C S E R V I C E M A N U A L Page 300 TORO-FLOW DIESEL ENGINE 1. Remove crankshaft damper following the procedure previously given under "Crankshaft Damper Replacement." C RANKSHAFT 2. Pry oil seal out of front cover assem bly. C O N E 3.
Page 312 Sec. 6B G M C S E R V I C E M A N U A L Page 301 TORO-FLOW DIESEL ENGINE SIDE SEA L G R O O V E 5 C ylinder Block 1 Suction Tube and 6 Pump D rive Shaft Screen A ssy.
Page 313 Sec. 6B G M C S E R V I C E M A N U A L Page 302 TORO-FLOW DIESEL ENGINE are driven from gear teeth machined on camshaft. The shaft, gear, and housing assembly (fig. 18) are installed in cylinder block at location normally occupied by ignition distributor on gasoline engine.
Page 314 Sec. 6B G M C S E R V I C E M A N U A L Page 303 TORO-FLOW DIESEL ENGINE jbiaoHaild. Chant HARD STARTING SYMPTOM A - LOW STARTING RPM REMEDY POSSIBLE CAUSES 1. Improper oil viscosity. 1.
Page 315 1. Improper grade or type of fuel in tank. Fill tank with proper fuel referring to current GMC D iesel Fuel Oil Bulletin. A BN O R M A L ENGINE OPERATION SYMPTOM A - UNEVEN RUNNING OR FREQUENT STALLING...
Page 316 6. Wrong grade or type of fuel. 6. Fill tank with correct fuel. (Refer to current GMC D iesel Fuel Oil Bulletin.) 7. Correct cooling system malfunction. 7. Engine overheating. 8. Check and correct as required.
Page 317 Sec. 6B G M C S E R V I C E M A N U A L Page 306 TORO-FLOW DIESEL ENGINE LOW ENGINE OIL PRESSURE (CONT’D) POSSIBLE CAUSES REMEDY 6. Overhaul or replace engine oil pump assembly. 6. Worn oil pump assem bly. 7.
Page 318 Sec. 6D Page 307 G M C S E R V I C E M A N U A L SECTION 6D £*taine M ountuu^i DESCRIPTION When inspecting engine mounts, check all at taching bolts and nuts for tightness. Refer to Torque Cushion-type mountings are used at all engine Chart shown below: mounting points.
Page 319 Sec. 6D G M C S E R V I C E M A N U A L Page 308 ENGINE M O U NTING S 2. With cushion components in place, lower the attaching bolts and nuts to torque specified in engine just enough to allow starting of all attach...
Page 320 Sec. 6K G M C S E R V I C E M A N U A L Page 309 SECTION 6K £n<fi*ie Goo-luta SuAtem COOLANT CIRCULATION V6 GASOLINE ENGINES The water pump, belt-driven from the engine crankshaft pulley, circulates the coolant through IN-LINE GASOLINE ENGINES the cooling system .
Page 321 DRAINING COOLING SYSTEM GMC Cooling System Cleaner or other com mercial cleaning solutions are especially effective 1. On Tilt Cab model, move heater control in removing rust, scale, and corrosion from the radiator and engine water passages.
Page 322 Sec. 6K G M C S E R V I C E M A N U A L Page 311 ENGINE COOLING SYSTEM 3. Attach a length of rubber tube to lower end CLEANING of overflow tube. This connection must be air-tight. 1.
Page 323 Sec. 6K G M C S E R V I C E M A N U A L Page 312 ENGINE COO LING SYSTEM Every two years the cooling system should be serviced by flushing with plain water, then com pletely refilling with a fresh solution of water and a high-quality, inhibited (permanent type) glycol base coolant meeting GM Specification 1899-M,...
Page 324 Sec. 6K G M C S E R V I C E M A N U A L Page 313 ENGINE COOLING SYSTEM b. If gauge shows high temperature under all E N G IN E O VERHEAT SW ITCH conditions, wire leading from gauge to engine unit (WIRE EN D RETAINED BY SCREW ) is shorted to ground.
Page 325 Sec. 6K G M C S E R V I C E M A N U A L Page 314 ENGINE COOLING SYSTEM WATER FILTER H o s e to H e a te r C o re R etu rn Lin e F ittin g Water filter (fig.
Page 326 Sec. 6K G M C S E R V I C E M A N U A L Page 315 ENGINE COOLING SYSTEM 1 Cover Bolt 2 Cover 3 Cover Gasket 4 Upper Plate 5 Element 6 Lower Plate 7 Spring 8 F ilter Body OUTLET 9 Plug...
Page 327 Sec. 6K G M C S E R V I C E M A N U A L Page 316 ENGINE COOLING SYSTEM (SEC. 9B) of this manual. Refer to AIR COM DRIVE BELT REPLACEMENT PRESSOR AND GOVERNOR (SEC. 6T) for adjust On some vehicles, several accessories may ment and replacement instructions for air com...
Page 328 Sec. 6M G M C S E R V I C E M A N U A L Page 317 SECTION 6M Z n c js in e , S u & t& Contents of this section are listed in Index below: Section Page No.
Page 329 Sec. 6M G M C S E R V I C E M A N U A L Page 318 FUEL SYSTEM— GASOLINE ENGINES 3. Block accelerator pedal down firmly against floor mat; then hold carburetor throttle lever in full throttle position and turn relay rod until end of rod fits freely into relay lever.
Page 330: Air Cleaners
Sec. 6M G M C S E R V I C E M A N U A L Page 319 FUEL SYSTEM— GASOLINE ENGINES Figure 4 — Accelerator Linkage (Tilt Cab M o d els) Push hand throttle completely in, then loosen If properly adjusted, initial movement of hand trunnion screw and move wire trunnion to make throttle control handle will cause increase in en...
Page 331: Fuel Pump
Sec. 6M G M C S E R V I C E M A N U A L Page 320 FUEL SYSTEM— GASOLINE ENGINES FUEL PUMP cannot escape from fuel chamber in pump and dia Fuel pumps (fig. 7) used on vehicles covered by this manual cannot be overhauled.
Page 332: Governors
Sec. 6M G M C S E R V I C E M A N U A L Page 321 FUEL SYSTEM— GASOLINE ENGINES the engine running. The pressure should be within the lim its given in "Specifications” for the par ticular engine.
Page 333 Sec. 6M G M C S E R V I C E M A N U A L Page 322 FUEL SYSTEM— GASOLINE ENGINES SINGLE TH RO AT TYPE W ITH DISTRIBUTOR V A C U U M A D V A N C E D U A L TH RO AT TYPE 9 Adjusting Screw 1 Governor Body...
Page 334 Sec. 6M G M C S E R V I C E M A N U A L Page 323 FUEL SYSTEM— GASOLINE ENGINES Figure 10— Vacuum Valve Operation ITypical) Automatic Spark Control vacuum transfer valve downward, providing an An automatic spark transfer valve is incor opening from below the governor throttle valve to porated in all velocity type governors.
Page 335 Sec. 6M G M C S E R V I C E M A N U A L Page 324 FUEL SYSTEM— GASOLINE ENGINES Figure J 4 — Spreading Filter Cover Figure 12— Operating Spring Coils Figure 13— Calibrating Governor eter to determine actual engine rpm.
Page 336 Sec. 6M G M C S E R V I C E M A N U A L Page 325 FUEL SYSTEM— GASOLINE ENGINES If "Governor Calibration" results in a surging or sary to bend cover to install; if so, flatten by tap sluggish condition, correct as instructed under ping with hammer (fig.
Page 337 Sec. 6M G M C S E R V I C E M A N U A L Page 326 FUEL SYSTEM— GASOLINE ENGINES U NIT 1 A c ce le r a to r L ever 7 T elesc o p ic Link 2 T hrottle Shaft D river 8 L ever 9 T hrottle Shaft...
Page 338 Sec. 6M G M C S E R V I C E M A N U A L Page 327 FUEL SYSTEM— GASOLINE ENGINES CARBURETOR ID E N T IF IC A T IO N N U M B E R L O C A T IO N IDLE MIXTURE S C R E W...
Page 339 Sec. 6M GMC OVE R HA UL MANUAL Page 328 FUEL SYSTEM— GASOLINE ENGINES ROCHESTER CARBURETOR TROUBLESHOOTING CHART (MODEL “M ”) C O M P L A IN T Locate the complaint by reading across the top of the complaint columns, then find Step 1. If Step 1 £...
Page 340: Rochester Carburetor
Sec. 6M G M C S E R V I C E M A N U A L Page 329 FUEL SYSTEM— GASOLINE ENGINE NOTE: Fuel seepage at the bowl to air norn mating surface is normal. This usually shows up as a discolored carburetor and is caused by wick- ing of the gasket in the area.
Page 341 Sec. 6M G M C S E R V I C E M A N U A L Page 330 FUEL SYSTEM— GASOLINE ENGINES carefully sliding slit portion of gasket over m eter ing rod holder. Then align gasket with dowels pro BEN D HERE TO ’A"...
Page 342: Bendix-Stromberg Carburetors
Sec. 6M G M C S E R V I C E M A N U A L Page 331 FUEL SYSTEM— GASOLINE ENGINES CARBURETOR INSTALLATION 4. Start vacuum and fuel lines at carburetor. 1. Be certain throttle body and intake manifold 5.
Page 343 Sec. 6M G M C S E R V I C E M A N U A L Page 332 FUEL SYSTEM— GASOLINE ENGINES BENDIX-STROMBERG CARBURETOR TROUBLESHOOTING CHART COMPLAINT Locate the complaint by reading across the top of the complaint columns, then find Step 1. If Step 1 does not remedy the complaint, move to Step 2 in that column.
Page 344 G M C S E R V I C E M A N U A l ______________________ pfge FUEL SYSTEM— GASOLINE ENGINES SHORT SC R E W S VIEW A M A IN VENT TUBE DISCHARGE ACCELERATO R PUMP ROD ID EN TIFIC ATIO N T A G IDENTIFICATION...
Page 345 Sec. 6M G M C S E R V I C E M A N U A L Page 334 FUEL SYSTEM— GASOLINE ENGINES and choke open. Air conditioning (when used) must be turned on during the carburetor adjustments. Engines Not Equipped With Controlled Combustion System - Modified (C.C.S.-M.) 1.
Page 346 Sec. 6M G M C S E R V I C E M A N U A L Page 335 FUEL SYSTEM— GASOLINE ENGINES ENGINE DATA CHART ENGINE MODELS 250 - 292 305E - 305C 351C - 351M Without Exhaust Emission Control IDLE* With Exhaust Emission Control Without Exhaust Emission Control...
Page 347 Sec. 6M G M C S E R V I C E M A N U A L Page 336 FUEL SYSTEM— GASOLINE ENGINES G a u g e (J - 8 8 2 4 ) (U se 3 / 1 6 " Side) C en ter of Float Figure 2 7 —...
Page 348: Exhaust Em Ission Control Systems
Sec. 6M G M C S E R V I C E M A N U A L Page 337 FUEL SYSTEM— GASOLINE ENGINES Figure 2 9 — Accelerator Pum p Adjustment moved from closed to wide open position as shown (305C, 305E, and 351C Engines) in figure 28.
Page 349: Air Injection Reactor S Y S T E M
Sec. 6M G M C S E R V I C E M A N U A L Page 338 FUEL SYSTEM— GASOLINE ENGINES CARBURETOR The carburetor used on C.C.S.-M. equipped V A C U U M LINE vehicles functions and operates the same as all other Bendix-Stromberg carburetors used on V6 engines.
Page 350 Sec. 6M G M C S E R V I C E M A N U A L Page 339 FUEL SYSTEM— GASOLINE ENGINES Figure 3 4 — Air Injection Pump high engine speeds the excess air is dumped through the pressure relief valve which is part of the air pump.
Page 351 Sec. 6M G M C S E R V I C E M A N U A L Page 340 FUEL SYSTEM— GASOLINE ENGINES Replacement 1. Loosen pump mounting bolt and pump ad justment bracket bolt, then swing pump until drive belt may be removed.
Page 352 Sec. 6M G M C S E R V I C E M A N U A L Page 341 FUEL SYSTEM— GASOLINE ENGINES AIR MANIFOLD, HOSE, AND TUBE Inspection (Refer to Fig. 32) 1. Inspect all hoses for deterioration or holes. 2.
Page 353 Sec. 6M G M C S E R V I C E M A N U A L Page 342 FUEL SYSTEM— GASOLINE ENGINES AIR INJECTION PUMP If none of the above conditions exist, and the air injection pump has excessive noise, remove Inspection and replace pump kit.
Page 354 Sec. 6M G M C S E R V I C E M A N U A L Page 343 FUEL SYSTEM— GASOLINE ENGINES A IR IN JE C T IO N R E A C T O R ( A . I . R . ) T R O U B L E D I A G N O S IS TROUBLE PROBABLE CAUSE REMEDY...
Page 355 G M C S E R V I C E M A N U A L FUEL SY ST EM - -GASOLINE ENGINES AIR IN JE C T IO N R E A C T O R ( A . I . R . ) T R O U B L E D I A G N O S I S ( C o n t ’d ) TROUBLE REMEDY PROBABLE CAUSE...
Page 356 Sec. 6M G M C S E R V I C E M A N U A L Page 345 FUEL SYSTEM --GASOLINE ENGINES G A S O L IN E E N G IN E S P E C I F I C A T I O N S BENDIX-STROMBERG CARBURETOR MODEL APPLICATION (EX C LU D IN G C A LIFO R N IA V E H IC L E S ) GM PART...
Page 357 MODEL NO... 7029012 7029011 FLO A T L E V E L " VELOCITY TYPE GOVERNOR SPECIFICATIONS KING-SEELEY MAX. GOVERNED MODEL GMC NO. ENGINE SPEED (R P M )* (STAMPED) (STAMPED) MODEL NO LOAD 901-623 2440843 305-C...
Page 358: Accelerator And Throttle Linkage Adjustment
Sec. 6M G M C S E R V I C E M A N U A L Page 347 ^ b ie A e l £ w a u i& f y u e i S u ite s n ACCELERATOR A N D THROTTLE LINKAGE ADJUSTMENT NOTE: For adjustment of accelerator linkage 3.
Page 359: Air Cleaners
Pasi’ e w _______________ G M C S E R V I C E M A N U A L ENGINE FUEL SYSTEM— DIESEL IDLE P O SIT IO N TO FULL THROTTLE 6 Clevis 7 Relay Lever to Idler Lever Rod 8 Sleeve 9 Lever 10 Bracket...
Page 360 Sec. 6M G M C S E R V I C E M A N U A L Page 349 ENGINE FUEL SYSTEM— DIESEL 1 Fuel Injection Pump 5 P ressu re Gauge 2 P ressure Gauge Gauge Adapter Fittings Stam ped 3 Secondary F ilter Secondary F ilter...
Page 361 Sec. 6M G M C S E R V I C E M A N U A L Page 350 ENGINE FUEL SYSTEM— DIESEL plug (7) and nut connecting line (11) to elbow at bottom of filter. 3. Remove bleeder plug (3), then remove drain plug (7) and drain filter into receptacle.
Page 362 Sec. 6M G M C S E R V I C E M A N U A L Page 351 fyuel Onjectio-n Syitem (V6 TORO-FLOW ENGINE) DESCRIPTION The hydraulic head bore is fitted with a pump plunger, the lower end of which seats in the tappet FUEL INJECTION PUMP ASSEMBLY roller guide.
Page 363: Fuel Injection System- Toro-Flow Engine
Sec. 6M G M C S E R V I C E M A N U A L Page 352 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE E X C E SS FUEL ST A R T IN G DEVICE DELIVERY V A LV E FUEL IN J E C T IO N N O Z Z L E H OLDER A S SE M B L Y...
Page 364 Sec. 6M G M C S E R V I C E M A N U A L Page 353 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE SPLINED SLEEVE W EIGHT SPIDER W EIGHT PUMP DRIVE SHAFT SPRING DRIVE GEAR SERVO VALVE LUBE OIL INLET FOLLOW -UP ROD T - 5 5 5 6...
Page 365 Sec. 6M G M C S E R V I C E M A N U A L Page 354 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE V IE W A V IE W B V IE W C V IE W D TO NOZZLE * ' ^ 9 BEGINNING...
Page 366 Sec. 6M G M C S E R V I C E M A N U A L Page 355 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE Quantity of fuel delivered per stroke is gov MAXIMUM DELIVERY (VIEW C, Fig. 4) erned by variation of the position of the metering If the position of metering sleeve (5) is raised sleeve (5) in relation to the fixed port closing p osi...
Page 367 Sec. 6M G M C S E R V I C E M A N U A L Page 356 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE FUEL INJECTION NOZZLE HOLDER ASSEMBLIES The fuel injection nozzle and holder assem blies are utilized to carry the high pressure fuel (red color in fig.
Page 368 Assembly isis 1. Fuel oil must conform to Factory recom mended specifications. Your GMC Dealer can sup Figure 6-Leai\-O ff Lines and Overflow Valve (Typical) ply you with these specifications. 2. Neglect of fuel filter service can be one of the major contributing factors to hard starting.
Page 369 FUEL SYSTEM TROUBLE D IAG N O SIS CHART ju < D T O P wJy/ <D / & cn S, <s~- /< & A , / s ' / <!^ /< § r > ? / * / y' V <...
Page 370 Sec. 6M G M C S E R V I C E M A N U A L Page 359 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE If a leak is apparent in the suction lines, filter or fittings, a sight glass or section of plastic line may be installed at inlet fitting on supply pump to determine if air is reaching pump through suc...
Page 371: Service Operations
Sec. 6M G M C S E R V I C E M A N U A L Page 360 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE bubbles rising to surface of oil. Bubbles indicate previously in this section. points where fuel leaks will occur during normal If no evidence of fuel leakage has been operation of supply pump.
Page 372 Sec. 6M G M C S E R V I C E M A N U A L Page 361 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE NOTE: Once fuel is noticed at the secondary filter, it may take one or two minutes more before clear fluid will flow, depending upon the condition of all filters.
Page 373 Sec. 6M G M C S E R V I C E M A N U A L Page 362 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE INJECTION TIMING 4. Remove the small hex bleeder plug (3, fig. 9) from the top of the secondary filter which has been suspended.
Page 374 Sec. 6M G M C S E R V I C E M A N U A L Page 363 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE mark on crankshaft damper is aligned with pointer in engine front cover (fig. 11). At this point pump should be injecting fuel into No.
Page 375 Sec. 6M G M C S E R V I C E M A N U A L Page 364 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE NOTE: It is possible in Step 2 previously, EWDRIVER A CLEARANCE SHOULD EXIST HERE. where engine idle is set to "Specifications," engine IF NOT, BACK OUT IDLE running and the cam nose touches the stop plate L _ _ >...
Page 376 Sec. 6M G M C S E R V I C E M A N U A L Page 365 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE 6. Place a quantity of adjusting spacers (4, fig. NOTE: When using the tool to make spacer s e lection, do not use the supply pump gasket between 15) between governor sleeve (8, fig.
Page 377 Sec. 6M G M C S E R V I C E M A N U A L Page 366 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE FUEL INJECTION NOZZLES BACK OUT IDLE ADJUSTING SPECIAL TOOL SCREW IF NECESSARY LOCATING A MISFIRING CYLINDER The procedure which follows may be used to HIGH SPEED SCREW...
Page 378 Sec. 6M G M C S E R V I C E M A N U A L Page 367 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE REFER TO "SETTING INJECTION NOZZLE may be necessary to tap lightly only with plastic VALVE OPENING PRESSURE" FOR NOZZLE TEST hammer on fuel lines.
Page 379 Sec. 6M G M C S E R V I C E M A N U A L Page 368 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE N EEDLE H O LD ER O RIFICE NEEDLE 1 Cup 6 Allen Wrench 2 Spray Tip 7 Cap Nut V A L V E B O D Y 3 N o z z le H older A ssy...
Page 380 Sec. 6M G M C S E R V I C E M A N U A L Page 369 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE and tighten cap nut (10) to 50 to 55 foot-pounds with W A RN IN G torque wrench.
Page 381 Sec. 6M G M C S E R V I C E M A N U A L Page 370 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE 7. Depress the pump handle slowly with a 10- second stroke and hold the pressure slightly (ap prox.
Page 382 Sec. 6M G M C S E R V I C E M A N U A L Page 371 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE TORQUE WRENCH ADAPTER! TORQUE WRENCH HYDRAULIC L HEAD TUBING CLAMP! ADAPTER TUBE N U T P L i w r y NOZZLE HOLDER T I G H T E N I N G N U T A T H Y D R A U L I C...
Page 383 Sec. 6M G M C S E R V I C E M A N U A L Page 372 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE Figure 2 9 — Installing Fuel Delivery Valve Retainer with Torque Wrench and a brush to remove any accumulated dirt from top of the injection pump assembly.
Page 384 Sec. 6M G M C S E R V I C E M A N U A L Page 373 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE INSTALLATION NOTE: Control unit and rod are held in place 1. Using a clean screwdriver, carefully insert by a retainer plate which is attached by two screw s it through the control unit opening in the pump equipped with lock wire.
Page 385 Sec. 6M G M C S E R V I C E M A N U A L Page 374 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE OVERFLOW VALVE ASSEMBLY The overflow valve assem bly components of which are shown in figure 34, is installed as shown in figure , item 5.
Page 386 Sec. 6M G M C S E R V I C E M A N U A L Page 375 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE CAUTION: As supply pump is remov ed the governor inner spring guide (1,fig. 35) and spring spacers are free to fall out of place.
Page 387 Sec. 6M G M C S E R V I C E M A N U A L Page 376 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE REMOVAL 3. Observe through opening in oil seal the 1. Remove equipment as necessary to provide position of flat in pump gear bore.
Page 388 Sec. 6M G M C S E R V I C E M A N U A L Page 377 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE 2. Place upper O-ring seal in groove in hy and is not repairable without removing the unit draulic head (fig.
Page 389 Sec. 6M G M C S E R V I C E M A N U A L Page 378 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE mark on crankshaft damper is aligned with pointer using care not to bend tubing. When tubing nuts are in engine front cover (fig.
Page 390 Sec. 6M G M C S E R V I C E M A N U A L Page 379 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE NOTE: The driven gear must be removed from stroke. Observe "INJ." mark on crankshaft damper hub on pump shaft before the injection pump a s...
Page 391 Sec. 6M G M C S E R V I C E M A N U A L Page 380 FUEL INJECTION SYSTEM— TORO-FLOW ENGINE 13. Install high pressure fuel lines referring line to the overflow valve assembly. to "High Pressure Fuel Line Installation" covered 11.
Page 392 Sec. 6T G M C S E R V I C E M A N U A L Page 381 SECTION 6T /lib Gamp.^e'L'La^i and Qau&isuM GENERAL INFORMATION The com pressor Model Number is shown on a name plate which is attached to the cylinder block. Midland-Ross and Bendix-Westinghouse air All com pressors are lubricated by oil from com pressors are interchangeable as complete a s...
Page 393 Sec. 6T G M C S E R V I C E M A N U A L Page 382 AIR COMPRESSORS A N D GOVERNORS through the crankshaft bearing cap and lubricates the connecting rod bearings. Some of the oil that flows between sides of connecting rod bearings and cheeks on crankshaft is sprayed upward.
Page 394 Sec. 6T G M C S E R V I C E M A N U A L Page 383 AIR COMPRESSORS A N D GOVERNORS DRIVE BELT M AINTENANCE A N D ADJUSTMENT Drive belts used on models covered by this manual are made of neoprene rubber with polyester cord.
Page 395 Sec. 6T G M C S E R V I C E M A N U A L Page 384 AIR COMPRESSORS A N D GOVERNORS REMOVING UNLOADER REMOVING UNLOADER PISTONS REMOVING OR REPLACING PISTON U6ING AIR PRESSURE UNLOADER SPRING Figure 4 —...
Page 396 Sec. 6T G M C S E R V I C E M A N U A L Page 385 AIR COMPRESSORS A N D GOVERNORS Assembly and Installation (Fig. 6) 1. Apply thin film of light engine oil to bush ing, diaphragm, and body before assembly.
Page 397 Sec. 6T G M C S E R V I C E M A N U A L Page 386 AIR COMPRESSORS A N D GOVERNORS 7 Housing 1 Adjuster Plug 8 Valve Assembly 2 Lock Nut 9 Governor Body 3 Spring 10 Filter 4 Spring Guide...
Page 398 Sec. 6T G M C S E R V I C E M A N U A L Page 387 AIR COMPRESSORS AND GOVERNORS Using a screwdriver, turn adjusting screw Restriction in com pressor cylinder head intake counterclockwise to raise pressure settings. Turn or discharge cavities or in discharge line.
Page 399 Sec. 6T __________________G M C S E R V I C E M A N U A L Page 388 AIR COMPRESSORS AND GOVERNORS NOTE The air com pressor is the only source of supply for the vehicle braking system . Faulty oper ation of the com pressor will result in improper function of brakes.
Page 400 Sec. 6Y G M C S E R V I C E M A N U A L Page 389 SECTION 6Y Qncjine £lect>iical This section, covering "ON-VEHICLE MAINTENANCE AND RE PLACEMENT” of charging system components, is divided into sections shown in the Index following: Subject Page No.
Page 401 Sec. 6Y G M C S E R V I C E M A N U A L Page 390 BATTERY prolonged driving, checking should be more fre quent because of more rapid loss of water. If elec trolyte level is found to be low, colorless, odorless, drinking water should be added to each cell until the liquid level rises to the split vent located in the vent well.
Page 402 Sec. 6Y G M C S E R V I C E M A N U A L Page 391 BATTERY 3. When attaching battery charger leads to the battery, connect charger positive lead to battery oooooo LO A D (VARIABLE positive terminal and connect charger negative RESISTANCE) lead to battery negative terminal.
Page 403 Sec. 6Y G M C S E R V I C E M A N U A L Page 392 BATTERY All cells read 1.95 or higher ( j * ) Cells read both above and below 1.95 L es s t h a n . 0 5 v ol t GOOD BATTERY Requires Charging GOOD BATTERY...
Page 404 Sec. 6Y G M C S E R V I C E M A N U A L Page 393 BATTERY FULL CHARGE HYDROMETER TEST Good Battery (Fig. 2, View A) The specific gravity of the electrolyte varies If all cells read 1.95 volts or more and the not only with the percentage of acid in the liquid, difference between the highest and lowest cell is but also with temperature.
Page 405 Sec. 6Y G M C S E R V I C E M A N U A L Page 394 BATTERY gravity obtained by the hydrometer may not give a long period of time. This is the only method that true indication of the concentration of acid in the will bring the battery to a full state of charge.
Page 406 Sec. 6Y G M C S E R V I C E M A N U A L Page 395 BATTERY vehicle and place it on a charging line. Charge the age drop in starter cable. Low voltage at starter battery until the specific gravity reaches 1.260- will prevent normal starter operation and will 1.280.
Page 407 Sec. 6Y G M C S E R V I C E M A N U A L Page 396 Sta/itUuf Stfiiem MODEL APPLICATION CHART STANDARD PART NUMBER Series LV/LA-4000; EM-4500M/V; EM-5500A/M/V; SM-5500M/Y; E M -6 5 0 0 A /V ..........1107375 Series SM-6500M/Y ...............
Page 408 Sec. 6Y G M C S E R V I C E M A N U A L Page 397 STARTING SYSTEM SOLENOID RETURN SPRING CONTACT SHIFT LEVER GROMMET PLUNGER FINGER BUSHING CONNECTORS B U S H IN G PINION STOP ARMATURE OVERRUNNING CLUTCH...
Page 409 Sec. 6Y G M C S E R V I C E M A N U A L Page 398 STARTING SYSTEM Figure 3 — Starter D isengagem ent and Figure 5 — Voltmeter Connections for Lock-Out (EG $500— 6500) Checking Circuits (Typical) r e la y op eratin g c o il to b reak c ir c u it to sta r te r R efer rin g to fig u r e 5 and w ith sta r te r crank ...
Page 410 Sec. 6Y G M C S E R V I C E M A N U A L Page 399 STARTING SYSTEM PRESS O N CLUTCH A S S H O W N TO TAKE UP M O V E M E N T STARTER REPLACEMENT REMOVAL 1.
Page 411 Sec. 6Y G M C S E R V I C E M A N U A L Page 400 STARTING SYSTEM Solenoid has two windings, the pulling winding and the holding winding. When ignition switch is turned to "START" position both windings are energized, producing a magnetic field which pulls the plunger in.
Page 412 Sec. 6Y G M C S E R V I C E M A N U A L Page 401 GENERAL IGNITION MAINTENANCE The ignition system consists of the source of By making the following inspection and adjust power (battery or generator) ignition switch, igni ments on the ignition system at regular intervals, causes of lowered performance will be located and tion coil, distributor, condenser, spark plugs, and...
Page 413 Sec. 6Y G M C S E R V I C E M A N U A L Page 402 IGNITION SYSTEM P O IN T E R Figure 1 — D iseng a g in g Ignition Switch Connector 3.
Page 414 Sec. 6Y G M C S E R V I C E M A N U A L Page 403 IGNITION SYSTEM RO TO R DISTRIBUTOR C O N D E N SE R DISTRIBUTOR COIL SC REW C A P SC R E W DISTRIBUTOR H O U S IN G —...
Page 415 Sec. 6Y G M C S E R V I C E M A N U A L Page 404 IGNITION SYSTEM DISTRIBUTOR excessively high voltage may cause oxidized con Distributor used on In-line engines is mounted on right side of engine and is driven by the engine tact points.
Page 416 Sec. 6Y G M C S E R V I C E M A N U A L Page 405 IGNITION SYSTEM Figure 7— Checking Breaker Arm Spring Tension "Specifications," at end of this section. Figure 8 — Setting Point O p ening Install rotor, position, and secure distrib...
Page 417 Sec. 6Y G M C S E R V I C E M A N U A L Page 406 IGNITION SYSTEM DISTRIBUTOR REMOVAL TO SP A R K PORT 1. Locate No. 1 cylinder spark plug wire on A B O V E CAR BU RETO R distributor cap, mark this position on cap and THROTTLE PLATES mark distributor housing adjacent to No.
Page 418 Sec. 6Y G M C S E R V I C E M A N U A L Page 407 IGNITION SYSTEM socket in distributor cap. Connect distributor prim IF ENGINE HAS NOT BEEN CRANKED (V-6 ENGINE MODELS) ary wire to negative (-) terminal on ignition coil. 1.
Page 419 Sec. 6Y G M C S E R V I C E M A N U A L Page 408 IGNITION SYSTEM 3. Open secondary circuit. Low Insulation Resistance. This condition per mits leakage which prevents condenser from hold 4. High voltage breakdown in secondary circuit. ing its charge.
Page 420 Sec. 6Y G M C S E R V I C E M A N U A L Page 409 IGNITION SYSTEM numbers lower (a "cooler" type) will generally be usually indicates the engine is operating at speeds or loads that are consistently greater than normal found satisfactory.
Page 421 Sec. 6Y G M C S E R V I C E M A N U A L Page 410 IGNITION SYSTEM SPARK PLUG INSTALLATION if too loose, or distortion of the spark plug body Be certain that the old gasket is removed be and change in gap setting or damage to the gasket fore installation of plug and that the gasket seat is if too tight.
Page 422 Sec. 6Y G M C S E R V I C E M A N U A L Page 411 AUe.n*iati*ia G uw etU Qenenatuuf, BtyUem The alternating current generator is used as standard and optional equipment on all vehicles covered by this manual. Refer to "Model Application Chart"...
Page 423 Spr* f!Y G M C S E R V I C E M A N U A L Page 412_______________________ A/C GENERATING SYSTEM WITH 1119507 REGULATOR WITH 1119515 REGULATOR Figure 1 — Schematic Diagram of A.C. C harging Circuit with Two-Unit Type Regulator (Typical) current regulation as long as the voltage is con...
Page 424 Sec. 6Y G M C S E R V I C E M A N U A L Page 413 A/C GENERATING SYSTEM A C C ESS PLUG TO VOLTAGE ADJUSTMENT Figure 3 — Two-Unit Type Regulator with Cover Removed pipe plug in cover and rotating the adjusting screw within regulator as explained later in this section.
Page 425 Sec. 6Y G M C S E R V I C E M A N U A L Page 414 A/C GENERATING SYSTEM O N VEHICLE MAINTENANCE, TESTS, A N D ADJUSTMENTS GENERATING SYSTEM M AINTENANCE 1. Battery undercharged (low specific gravity of electrolyte).
Page 426 Sec. 6Y G M C S E R V I C E M A N U A L Page 415 A /C GENERATING SYSTEM Jumper Lead W I R I N G H A R N E S S C O N N E C T O R W IR IN G H A R N E S S T P M -9 7 3 4 C O N N E C T O R...
Page 427 Sec. 6Y G M C S E R V I C E M A N U A L Page 416 A/C GENERATING SYSTEM lAfSJf 1 C 4 iT [| | j W IR IN G H A R N E S S T-641-1 C O N N E C T O R A T R E G U L A T O R Figure 9 —...
Page 428 Sec. 6Y G M C S E R V I C E M A N U A L Page 417 A/C GENERATING SYSTEM Figure 1 7 — Connections for Testing Regulator Voltage Setting (Two-Unit Type Regulator) ulator "F" terminal, and connect a jumper lead Figure 10—...
Page 429 Sec. 6Y G M C S E R V I C E M A N U A L Page 418 A/C GENERATING SYSTEM volts higher than on lower contacts. The most desirable method for determining that the regulator is operating on the lower set of contacts when the cover is installed is to use ear...
Page 430 Sec. 6Y G M C S E R V I C E M A N U A L Page 419 A/C GENERATING SYSTEM positive terminal and regulator No. 3 terminal, If any circuit defects are found, yet the battery and jumper lead is connected between regulator remains undercharged, raise the setting by 0.3 No.
Page 431 Sec. 6Y G M C S E R V I C E M A N U A L Page 420 A/C GENERATING SYSTEM socket on generator. Pull rubber boot off "BAT" terminal and remove terminal nut. Disconnect wire from "GRD" terminal and remove the wiring clip. On 130-amp generator, remove nuts and wash...
Page 432 Sec. 6Y G M C S E R V I C E M A N U A L Page 421 A/C GENERATING SYSTEM On 130-amp generator, connect harness leads "Drive Belt Tension Adjustment" previously. Tight to respective generator terminals, then install at en flange type lock nuts and mounting bolts to taching nuts and washers.
Page 433 Sec. 6Y G M C S E R V I C E M A N U A L Page 422 A/C GENERATING SYSTEM A rm a tu re Stop Su p p o rt Sp rin g A ir G a p (Check (B end if N e ce ssary ) (Bend if N e cessary) W ith Points...
Page 434 Sec. 6Y G M C S E R V I C E M A N U A L Page 423 A/C GENERATING SYSTEM No. 7 No. 1 No. 4 OUTPUT TRANSISTOR No. 6 No. 3 No. 5 -5 5 8 9 Figure 21 —...
Page 435 Sec. 6Y G M C S E R V I C E M A N U A L Page 424 A/C GENERATING SYSTEM REGULATOR R3 V O LTA G E DIVIDER R ESISTO R R2 POTENTIOM ETER T R A N S IST O R No.
Page 436 Sec. 6Y G M C S E R V I C E M A N U A L Page 425 A/C GENERATING SYSTEM Figure 2 5 — Checking Regulator Circuits Figure 2 6 — Checking Transistors for Shorts FILTER CAPACITOR DRIVER TRANSISTOR (PART 8, Fig.
Page 437 Sec. 6Y G M C S E R V I C E M A N U A L Page 426 A/C GENERATING SYSTEM OUTPUT TRANSISTOR VOLTAGE DIVIDER RESISTOR R-3 (PART 15, Figs. 26 and 27) (PART 19, Fig. 25) In figure 26, if both readings in Step 1 are If one reading is infinite or nearly infinite, or zero, or if both readings are very low and identical, if both readings are infinite or nearly infinite, the...
Page 438 Sec. 6Y G M C S E R V I C E M A N U A L Page 427 A/C GENERATING SYSTEM on the vehicle, voltage should be set 0.1 volt lower 5. Connect a test voltmeter between regulator than the middle range given in "Specifications"...
Page 439 Sec. 6Y G M C S E R V I C E M A N U A L Page 428 A/C GENERATING SYSTEM...
Page 440 Sec. 6Y G M C S E R V I C E M A N U A L Page 429 A/C GENERATING SYSTEM...
Page 441 Sec. 6Y G M C S E R V I C E M A N U A L Page 430 A/C GENERATING SYSTEM SPECIFICATIONS ALTERNATING CURRENT GENERATING SYSTEM SPECIFICATIONS GENERATOR MODEL 1100842 1100849 1117754 1117128 M ake......... Delco-Remy Delco-Remy Delco-Remy Delco-Remy Rotation (View ing Drive En d ).
Page 442 Sec. 7A G M C S E R V I C E M A N U A L Page 431 SECTION 7 < and GlutcUel Section Page No. Transmission Control Linkage ......Transmission On-Vehicle Service Operations . Clutch C on trols............C lu tch es...............
Page 443 Sec. 7A G M C S E R V I C E M A N U A L Page 432 TRANSMISSION CONTROL LINKAGE transm issions b a s i c a l l y same construction. REMOVAL NOTE: Key numbers in following text refer to figure 2.
Page 444 Sec. 7A G M C S E R V I C E M A N U A L Page 433 TRANSMISSION CONTROL LINKAGE Expansion Plug Remote Control Shift Rail Screw and Lock Washer Assy. Cover Gasket Remote Control Cover Lock Nut Shift Yoke Guide Shift Rail Boot Shift Rail Yoke...
Page 445 Sec. 7A G M C S E R V I C E M A N U A L Page 434 TRANSMISSION CONTROL LINKAGE 1 Expansion Plug 11 Oil Seal 2 Shift Rail 12 Roll Pin 3 Nut 13 Nut 4 W asher 14 W asher 15 Selector L ever 5 Yoke Guide...
Page 446 Sec. 7A G M C S E R V I C E M A N U A L Page 435 TRANSMISSION CONTROL LINKAGE lubricant recommended in LUBRICATION (SEC. 0) Cleaning and Inspection 1. Clean all metal parts thoroughly in clean of this manual.
Page 447 Sec. 7A Page 436 G M C S E R V I C E M A N U A L TRANSMISSION CONTROL LINKAGE Figure 5 — Accelerator a n d TV Linkage...
Page 448 Sec. 7A G M C S E R V I C E M A N U A L Page 437 TRANSMISSION CONTROL LINKAGE “ THROUGH-DETENT” shift points are not cor 50 rpm below the engine governed speed. If up rect, the TV mechanism in the transmission may shifts do not occur at specified rpm, adjust as be sticking.
Page 449 Sec. 7A G M C S E R V I C E M A N U A L Page 438 TRANSMISSION CONTROL LINKAGE “ R, N, 3-6, 3-5, 3-4, and 1-2,” just before the lever hits the “ stops” incorporated in the shift control cover.
Page 450 Sec. 7A G M C S E R V I C E M A N U A L Page 439 TRANSMISSION CONTROL LINKAGE RETARDER ADJUSTMENT The transmission retarder (when used) on vehicles covered by this manual is actuated by either hydraulic or mechanical type controls. Adjustment for each system is described as follows:...
Page 451 Sec. 7A __________________G M C S E R V I C E M A N U A L Page 440 TRANSMISSION CONTROL LINKAGE NOTE: On all vehicles equipped with Allison Automatic Transmissions, it is recommended that the transmission be filled with DEXRON automatic transmission fluid.
Page 452 Sec. 7B G M C S E R V I C E M A N U A L Page 441 SECTION 7B Vehicle SeAuice Opesvationl NOTE: Allison transmission overhaul information is contained in separate publication Form Number SA 1126E. Subject Page No.
Page 453 Sec. 7B G M C S E R V I C E M A N U A L Page 442 TRANSMISSION ON-VEHICLE SERVICE propeller shafts, joint angle, rear axle, differen 1. Growl and Humming, or more serious, a tials, etc. grinding noise.
Page 454 Sec. 7B G M C S E R V I C E M A N U A L Page 443 TRANSMISSION ON-VEHICLE SERVICE When the shift lever moves directly into mechanism preventing full engagement of the the manual shift position without resistance, the sliding clutch gear, or - raking of teeth will be audible and felt through If the gear has been shifted completely...
Page 455 Sec. 7B G M C S E R V I C E M A N U A L Page 444 TRANSMISSION ON-VEHICLE SERVICE BEARING REPLACEMENT squeezed out of position, pieces still under bear ing caps, clutch housing, power take-off, and It is far more difficult to remove bearings from a shaft than to put them on.
Page 456 Sec. 7B G M C S E R V I C E M A N U A L Page 445 TRANSMISSION ON-VEHICLE SERVICE 10. If vehicle is equipped with power take-off GEARSHIFT LEVER remove unit and controls from transmission. Place protective covering over opening. 11.
Page 457 Sec. 7B G M C S E R V I C E M A N U A L Page 446 TRANSMISSION ON-VEHICLE SERVICE (SEC. 4D) of this manual. 3. Remove parking brake from rear of trans m ission as described in “ PARKING BRAKE” (SEC.
Page 458 Sec. 7D G M C S E R V I C E M A N U A L Page 447 SECTION 7D QlutcU Go*tt>voli All conventional cab and cowl models, and also PS4500 are equipped with mechanical clutch control linkage. Tilt cab models are equipped with hy- draulically actuated clutch controls.
Page 459 Sec. 7D G M C S E R V I C E M A N U A L Page 448 CLUTCH CONTROLS MECHANICAL LINKAGE CONTROLS MECHANICAL LINKAGE ADJUSTMENTS 2. Apply approximately 5 pounds force to the push rod in direction of arrow (E) to eliminate clearance between release bearing and internal All Models Except PS4500 release levers.
Page 460 G M C S E R V I C E M A N U A L _______________________ Page449 CLUTCH CONTROLS ALL C O N V . M O D E L S EXCEPT “ ES” M O D E L S 8 Nylon Seat 1 Engine 9 Lock Spring...
Page 461 Sec. 7D G M C S E R V I C E M A N U A L Page 450 CLUTCH CONTROLS Figure 6 — Clutch Hydraulic System (“L” M odels) 3. Make sure return spring at release fork is not weak or broken. 4.
Page 462 Sec. 7D G M C S E R V I C E M A N U A L Page 451 CLUTCH CONTROLS Figure 9 — Master Cylinder Push Rod Check and Adjustment (“L” Models) door located at front of driver's seat riser as shown in figure 7.
Page 463 Sec. 7D E M A N U A L ______________________ G M C S E R V I Page 452 CLUTCH CONTROLS nut and wedge. Remove the tool, lock adjusting nut with lock nut and install the slave cylinder return spring.
Page 464 Sec. 7D G M C S E R V I C E M A N U A L Page 453 CLUTCH CONTROLS CLUTCH PEDAL A N D BUSHING ASSEMBLY REPLACEMENT (ALL “L” MODELS) REMOVAL (Refer to Fig. 8) 1. Tilt cab forward. IMPORTANT: Make sure cab safety catch at right front pivot mounting is securely engaged.
Page 465 Sec. 7D G M C S E R V I C E M A N U A L Page 454 CLUTCH CONTROLS CLUTCH SLAVE CYLINDER The clutch slave cylinder (fig. 14) mounted at side of clutch assembly (fig. 15) activates the mechanical clutch release fork to disengage clutch when cylinder is pressurized.
Page 466 Sec. 7E G M C S E R V I C E M A N U A L Page 455 CLUTCHES Push Rod Check and Adjustment.’' INSTALLATION Attach hydraulic line to slave cylinder 1. Bolt slave cylinder assem bly to engine and bleed air from system at slave cylinder bleed (fig.
Page 467 Sec. 7E G M C S E R V I C E M A N U A L Page 456 CLUTCHES PACK THIS RECESS T-3540 Figure 1 — Use of Blocks Between Release Levers and Cover Figure 3 — Release Bearing and Support Assem bly (Typical) Figure 4 —...
Page 468 Sec. 7E G M C S E R V I C E M A N U A L Page 457 CLUTCHES INSPECTION A N D REPAIR FLYWHEEL Inspect flywheel surface which is contacted The following procedures apply to all clutch by the clutch facing.
Page 469 Sec. 7E G M C S E R V I C E M A N U A L Page 458 CLUTCHES install ball stud retainer spring in fork. Force a sm all quantity of high temperature grease. NOTE: The clutch release bearing on some ball stud into fork recess until engaged by spring.
Page 470 Sec. 7E G M C S E R V I C E M A N U A L Page 459 CLUTCHES Total lift readings should be .055” to .075” . If above measures fail to correct the trouble, NOTE: Excessively high readings indicate checke driven disc with clutch pedal depressed (it that the diaphragm spring is being over-stressed should spin freely with transmission in neutral).
Page 471 ________________G M C S E R V I C E M A N U A L PageTeo CLUTCHES Always Be Sure To Readjust The Clutch Linkage After Performing Clutch Maintenance Operations.
Page 472 Sec. 8A G M C S E R V I C E M A N U A L Page 461 SECTION 8 fyu el and &iclicLu4Jt Section Page No. Fuel T a n k ............Exhaust System ..........NOTE: Refer to ENGINE FUEL SYSTEM (SEC. 6M) for information pertaining to fuel filters and fuel pumps.
Page 473 Sec. 8A G M C S E R V I C E M A N U A L Page 462 FUEL TANK A N D EXHAUST Figure 4 — Flaring Operation IPositioning Tubing) FUEL LINE INSTALLATION In making up fuel lines, it is important that Figure 2 —...
Page 474 Sec. 8A G M C S E R V I C E M A N U A L Page 463 FUEL TANK AND EXHAUST RAM GUIDE LATCH PLATE UPSET FLARE PUNCH , RAM DIE B L O C K \ TUBE STOP PLATE...
Page 475 Sec. 8A G M C S E R V I C E M A N U A L Page 464 FUEL TANK A N D EXHAUST SLOTTED DOWEL SPANNER WIRE TERMINAL LUGS SPANNER WRENCH RETAINING RING FUEL TANK FUEL TANK ST RA P Figure 10—...
Page 476 Sec. 8A G M C S E R V I C E M A N U A L Page 465 FUEL TANK A N D EXHAUST resistance occurs which results in a proportional to frame. Start engine and check for leaks and current change in the dash gauge coils.
Page 477 Sec. 8A G M C S E R V I C E M A N U A L Page 466 FUEL TANK A N D EXHAUST FUEL GAUGE SYSTEM TROUBLE DIAGNOSIS CHART POSSIBLE COMPLAINT AT D A S H W IR IN G C O N N E C T O R IG N IT IO N S W IT C H T A N K...
Page 478 Sec. 8B G M C S E R V I C E M A N U A L Page 467 SECTION 8B £ * J t a u it S u it e m GENERAL INFORMATION absolutely necessary to operate vehicle when an exhaust leak exists, use extreme caution and keep Exhaust system configurations vary according cab well ventilated.
Page 479 Sec. 8B ________________ G M C S E R V I C E M A N U A L Page 468 FUEL TANK A N D EXHAUST When working on fuel system , fire fighting and appropriate safety equipment should be provided in accordance with local fire and safety regulations.
Page 480 Sec. 9A G M C S E R V I C E M A N U A L Page 469 SECTION 9 Ste&Una Su&tem Contents of this section are listed in Index below: Section Page No. Mechanical S te e r in g ............Power Steering ..............
Page 481 Sec. 9A G M C S E R V I C E M A N U A L Page 470 MECHANICAL STEERING 22 Adjuster Lock Nut 1 Lash Adjuster Lock Nut 11 Pitman Shaft Oil Seal 23 Cup and Adjuster Assembly 12 Housing Bushing 2 Side Cover 13 Steering Gear Housing...
Page 482 Sec. 9A G M C S E R V I C E M A N U A L Page 471 MECHANICAL STEERING Fire Wall Bracket 9 Stop Clamp 10 Upper Steering Shaft Retainer and Floor Seal 11 Upper Shaft Yoke Screw Clamp 12 Center Universal Joint Assy.
Page 483 Sec. 9A G M C S E R V I C E M A N U A L Page 472 MECHANICAL STEERING ceptible end play in the worm. 2. Using spring scale (J-544-01), checksteer- ing wheel rim pull as outlined previously. Turn adjuster screw until a pull of 1% to 2 pounds is obtained on spring scale at steering wheel.
Page 484 Sec. 9A G M C S E R V I C E M A N U A L Page 473 MECHANICAL STEERING FLEXIBLE C O U PLIN G Lower Shaft Yoke Yoke Clamp CLAMP BOLT Steering Gear Worm Shaft Steering Gear Mounting Bracket Pitman Shaft Nut Pitman Arm...
Page 485 Sec. 9A G M C S E R V I C E M A N U A L Page 474 MECHANICAL STEERING be properly adjusted at all tim es. NOTE: Whenever any steering linkage com ponents have been repaired or replaced, check steering geometry and front end alignment as des...
Page 486 Sec. 9A G M C S E R V I C E M A N U A L Page 475 MECHANICAL STEERING 2. Inspect tie rod for bent condition. If tie rod is bent more than 5 degrees, replace assembly. If tie rod is bent less than 5 degrees, tie rod may be straightened provided cold straightening method is used.
Page 487 Sec. 9A G M C S E R V I C E M A N U A L Page 476 MECHANICAL STEERING BOOT C LAM P PRESSURE HOSE S PRESSURE SLIP Y O K E CHECKING GAUGE LUBRICATION FITTING 'CLAM P Y O K E IGAUGE VALVE RETURN...
Page 488 Sec. 9A G M C S E R V I C E M A N U A L Page 477 MECHANICAL STEERING Install retainer and horn button cap and connect directional signal wiring harness to chassis wiring harness connector. STEERING COLUMN A N D SHAFT (CAB A N D COWL MODELS) REMOVAL (Refer to Fig.
Page 489 Sec. 9A G M C S E R V I C E M A N U A L Page 478 MECHANICAL STEERING 1 Tube Yoke Bushings 2 Snap Rings 3 Cork Washers 4 Tube Yoke Center Cross 5 Washer 6 Yoke, Tube, & Sleeve Assy. 7 Felt Washer 8 Dust Cap 9 Yoke Shaft...
Page 490 Sec. 9A G M C S E R V I C E M A N U A L Page 479 MECHANICAL STEERING 1 Notch in Receiver Cup 6 Steering Wheel Hub 7 Horn Contact 2 Retainer Screw 3 Bushing Spacer Cartridge 8 Contact Brush 4 Receiver Cup...
Page 491 G M C S E R V I C E M A N U A L Page 480_______________________ MECHANICAL STEERING 9 Steering Wheel 1 D irection al Housing Spring 2 Upper Steering Shaft 10 Steering Wheel Hub 17 Stop Clamp 3 Switch Support 11 Steering Wheel Lock Nut 18 Center Universal Joint Assy.
Page 492 Sec. 9A G M C S E R V I C E M A N U A L Page 481 MECHANICAL STEERING STEERING COLUMN A N D SHAFT INSPECTION Inspect steering column components and re (“P” MODELS) place or repair as described previously in "In REMOVAL (Refer to Fig.
Page 493 Sec. 9A G M C S E R V I C E M A N U A L Page 482 MECHANICAL STEERING of floor until it is properly seated. 5. Place cam and horn contact assembly (8) at under-side of steering wheel hub (10), with horn contact extension inserted in hub.
Page 494 Sec. 9A G M C S E R V I C E M A N U A L Page 483 MECHANICAL STEERING splines lightly. Align arrows on yoke shaft, and 2. Referring to figure 12, remove directional slip joint tube. Slide shaft into tube and crimp control lever from control switch.
Page 495 Sec. 9A G M C S E R V I C E M A N U A L Page 484 MECHANICAL STEERING to multiple connector under dash. 10. Test action of steering wheel for bind, 9. Secure trailer hand brake control to column looseness, or chucking and make adjustments, if if previously removed.
Page 496 Sec. 9A G M C S E R V I C E M A N U A L Page 485 MECHANICAL STEERING PROBLEM VIBRATION OR SHIMMY CAUSE 1. Tires, wheels, or brake drums out of balance. 2. Bent wheel or out of round tire. 3.
Page 497 Sec. 9A G M C S E R V I C E M A N U A L Page 486 MECHANICAL STEERING MECHANICAL STEERING SPECIFICATIONS STEERING GEAR APPLICATION CHART GEAR GEAR CENTER* TRUCK MODELS MODEL RATIO POSITION Steel Tilt Cab Models...................... 553-D-17 28.14 to 1 6 O’Clock...
Page 498 Sec. 9B G M C S E R V I C E M A N U A L Page 487 SECTION 9B Po-w&i Stee/Una Contents of this section are listed in Index below: Section Page No. D e s c r ip t io n .......................487 Maintenance ....................487 Power Steering Gear and Control V a l v e ..........489...
Page 499 Sec. 9B G M C S E R V I C E M A N U A L Page 488 POWER STEERING 3. Turn wheels to right and left to wheel P re ssu re "stops" to eliminate air pockets in the power cyl C h e c k in g inder.
Page 500 Sec. 9B G M C S E R V I C E M A N U A L Page 489 POWER STEERING 3. Close shut-off valve and observe pressure gauge. Pressure should be 1000 to 1100 psi. NOTE: Do not close valve for more than a few seconds, as this would increase fluid temperature and cause excessive pump wear.
Page 501 Sec. 9B G M C S E R V I C E M A N U A L Page 490 POWER STEERING Valve Body Top Cover Valve Spool Valve Spool Dampener Upper Thrust Bearing Spool Spring Stub Shaft Seal Seal Retaining Ring Stub Shaft Torsion Bar Pin Torsion Bar Sleeve...
Page 502 Sec. 9B G M C S E R V I C E M A N U A L Page 491 POWER STEERING tach steering gear assembly to frame left side at rear of this section. It is intended as a quick member.
Page 503 Sec. 9B G M C S E R V I C E M A N U A L Page 492 POWER STEERING External leakage may be due to loose hose con nections or damaged hose, adjuster plug seals or torsion bar seals. Correct external leaks as follows: CAUSE REMEDY...
Page 504 Sec. 9B G M C S E R V I C E M A N U A L Page 493 POWER STEERING From cavity (1) the oil flows into passage (2) P u m p R in g P u m p Rotor which is controlled in size to provide definitely known oil velocities.
Page 505 Sec. 9B G M C S E R V I C E M A N U A L Page 494 POWER STEERING 9 ::v :v :;:v :v * v X $ VIEW A -P U M P O PERATIO N -LO W SPEED LEGEND | !!!| DISCHARGE OIL SUPERCHARGE OIL...
Page 506 Sec. 9B G M C S E R V I C E M A N U A L Page 495 POWER STEERING Rotor Slipper Flow Control Valve O-Ring Seal Snap Ring Control Valve Plug Pump Body Metering Insert Control Valve Spring Relief Valve Assembly Rotor Slipper Spring...
Page 507 Sec. 9B G M C S E R V I C E M A N U A L Page 496 POWER STEERING PUMP LEAKS increased as when making a full cramped U-turn. The noise is caused by the relief valve and is normal.
Page 508 Sec. 9B G M C S E R V I C E M A N U A L Page 497 POWER STEERING at fault. When the first test is below specifications #2 and comparing it with test No. 1. and the second test is not more than 50 psi greater, Test #2 is Performed With the Oil Circuit the pump is at fault.
Page 509 Sec. 9B G M C S E R V I C E M A N U A L Page 498 POWER STEERING cylinder in tight; then back off to nearest cotter in the guide assembly while at the same time hold pin hole and install new cotter pin.
Page 510 Sec. 9B G M C S E R V I C E M A N U A L Page 499 POWER STEERING cylinder housing, until it bottoms. Using a grease components, refer to "Power Steering Specifica pencil or other suitable marking device, place tions"...
Page 511 Sec. 9B G M C S E R V I C E M A N U A L Page 500 POWER STEERING QUICK REFERENCE TROUBLE SHOOTING CHART NOTE: Some of the remedial procedures suggested for conditions out lined in this chart constitute overhaul of components which is not within the scope of this manual.
Page 512 Sec. 9B G M C S E R V I C E M A N U A L Page 501 POWER STEERING 8. Pump inoperative, Vanes not installed properly. Install vanes properly. poor, or no assist. Free up by removing burrs or dirt. Vanes sticking in rotor slots.
Page 513 Sec.9B G M C S E R V I C E M A N U A L Page 502 POWER STEERING CONTROL VALVE AND POWER STEERING GEAR (Cont.) C O ND ITIO N CAUSE REMEDY 8. Truck leads to one Due to front end m isalignm ent.
Page 514 Sec. 9B G M C S E R V I C E M A N U A L Page 503 POWER STEERING CONTROL VALVE AND POWER STEERING GEAR (Cont.) CONDITIO N CAUSE REMEDY Hard steering when Comparing the m aximum pressures obtained in these two tests parking.
Page 515 Sec. 9B G M C S E R V I C E M A N U A L Page 504 POWER STEERING SPECIFICATIONS POWER STEERING GEAR SPECIFICATIONS TRUCK GEAR GEAR CENTER MODEL MODEL RATIO POSITION S T E E L T IL T CA B M O D E L S ........553-DV-54 28.14-1 P S -4 5 00 ..............
Page 516 Sec. 9B G M C S E R V I C E M A N U A L Page 505 POWER STEERING SPECIFICATIONS (CONT.) HYDRAULIC PUMP SPECIFICATIONS V A N E T Y P E PUMP M a k e ......................................... Saginaw Steering Gear Division T y p e ..................................................Vane M odel................................................
Page 517 Sec 9B ______________________ G M C S E R V I C E M A N U A L Page 506 POWER STEERING A satisfactory steering system depends upon maintaining components in good condition, with a minimum amount of wear permitted. Proper align ment, and lubrication will pay dividends in driver satisfaction, and in tire economy.
Page 518 Sec. 10 G M C S E R V I C E M A N U A L Page 507 SECTION 10 'Wheels ^ine.6. C u n d nuts on right side of vehicle have right-hand Wheels used on vehicles covered in this manual threads, and studs and nuts on left side have left- are D isc, Cast, or Budd type (fig.
Page 519 Sec. 10 G M C S E R V I C E M A N U A L Page 508 WHEELS A N D TIRES Figure 3 — W heel N ut Tightening Sequence for Cast W heels 2. Starting at bottom, tighten#l nut 15-20foot This should not exceed 3/32-inch.
Page 520 Sec. 10 G M C S E R V I C E M A N U A L Page 509 WHEELS A N D TIRES on all trucks should receive the same amount of careful system atic, and regular maintenance as do other operating units.
Page 521 Sec. 10 G M C S E R V I C E M A N U A L Page 510 WHEELS A N D TIRES but not actually breaking. Replacing only the one broken stud and remounting wheel will then set the stage for a second and possibly more serious fail...
Page 522 Sec. 10 G M C S E R V I C E M A N U A L Page 511 WHEELS A N D TIRES IMPORTANT: When servicing wheels, care should be taken to prevent wheel discs, and rims D IM E N S IO N from becoming mixed.
Page 523 Sec. 10 G M C S E R V I C E M A N U A L Page 512 WHEELS A N D TIRES TORQUE FT. LBS. W ITH D IS C T Y P E W H EE LS (P S 4 5 0 0 )................... 300-400 W ITH D IS C T Y P E W H EE LS (E X C E P T PS 4 5 0 0 )................
Page 524 Sec. 11 G M C S E R V I C E M A N U A L Page 513 SECTION 1 1 S h eet M etal (CONVENTIONAL CAB A N D COW L MODEL TRUCKS) Information in this section covers replacement and adjustment of sheet metal components.
Page 525 Sec. 11 G M C S E R V I C E M A N U A L Page 514 SHEET METAL FEN D ER A N D SK IRT A S S E M B L Y Figure 3 — Radiator Shell Flexible M ounting SUPPORT BRACKET M O U N T IN G BOLT HOLES...
Page 526 Sec. 11 G M C S E R V I C E M A N U A L Page 515 SHEET METAL RUNN IN G BOARD REPLACEMENT (Refer to Figure 6) REMOVAL 1. Remove bolt(s), nut(s), and washer(s) which attach running board to fender. Remove bolt spac e r s ) , if used.
Page 527 Sec. 11 G M C S E R V I C E M A N U A L Page 516 SHEET METAL IMPORTANT: DO NOT OVER-ADJUST TO NOTE: If collision repairs were made or if new sheet metal parts were installed, it may be CAUSE ENGINE FAN TO CONTACT CORE.
Page 528 Sec. 12 G M C S E R V I C E M A N U A L Page 517 SECTION 12 Sleci^UccU and 9vUi^uune*iti This section, covering maintenance of chassis electrical system and units, is divided into sub-sections as shown in the Index following: Section Page No.
Page 529 Sec. 12 G M C S E R V I C E M A N U A L Page 518 CHASSIS ELECTRICAL A N D INSTRUMENTS CAUTION: Never replace a wire with W IRING HARNESS one of a smaller size. DO NOT replace a CONNECTOR fusible link with a wire of a larger size.
Page 530 G M C S E R V I C E M A N U A L ________________pfge5i9 CHASSIS ELECTRICAL AND INSTRUMENTS Figure 4 — Typical Fuse Block (PS4500) IMPORTANT: When replacing fuses, circuit pry lock on terminal clips down to assure a firm connection when terminals are inserted into the breakers, or flashers, be certain replacement is the same part number as defective component.
Page 531 Sec. 12 G M C S E R V I C E M A N U A L Page 520 CHASSIS ELECTRICAL A N D INSTRUMENTS TILT CAB MODELS Chassis junction block (fig. 7) is located under left-hand step riser panel and is accessible when door is open and cover is removed.
Page 532 Sec. 12 G M C S E R V I C E M A N U A L Page 521 CHASSIS ELECTRICAL A N D INSTRUMENTS operating properly, repair or replace the speed ometer head. Replace the cable if kinked or broken. C h a ssis Jun ctio n Block If the speedometer head, adapter, and cable are operating properly, replace the speedometer drive...
Page 533 Sec. 12 G M C S E R V I C E M A N U A L Page 522 CHASSIS ELECTRICAL A N D INSTRUMENTS The marker lamp switch on instrument panel flows directly through relay contacts and out No. 3 terminal to the horn.
Page 534 Sec. 12 G M C S E R V I C E M A N U A L Page 523 CHASSIS ELECTRICAL AN D INSTRUMENTS cable from battery before removing instrument INSTALLATION cluster to prevent accidental grounding at ammeter. 1. Position each gauge or unit in cluster and install nuts and washers to secure to mounting 1.
Page 535 Sec. 12 G M C S E R V I C E M A N U A L Page 524 CHASSIS ELECTRICAL AND INSTRUMENTS LEFT CLUSTER R IG H T CLUSTER 1 Turn Signal T ell-ta le 7 Differential Lock T ell-tale 13 Fuel Gauge 2 Oil Pressure Gauge 8 Hi Beam Indicator...
Page 536 Sec. 12 G M C S E R V I C E M A N U A L Page 525 CHASSIS ELECTRICAL A N D INSTRUMENTS starts and terminates at a terminal post. Each retaining clips, two at top and two at bottom. Holes instrument and tell-tale light bulb is a wedge base are provided in instrument panel to permit using hooked tool (J-7900) to depress clips and release...
Page 537 Sec. 12 G M C S E R V I C E M A N U A L Page 526 CHASSIS ELECTRICAL AND INSTRUMENTS rw ii— - - ------- RETAINING RING SPRING VERTICAL ADJUSTING SCREWS HOOKED TOOL HORIZONTAL gj|| ADJUSTING SCREW S 3 1 V IE W B RETAINING RING ATTACHING SCREWS...
Page 538 Sec. 12 G M C S E R V I C E M A N U A L Page 527 CHASSIS ELECTRICAL AND INSTRUMENTS 3. P ress in on the assembly and rotate slightly ! Vertical | Retaining to engage horizontal and vertical adjusting screws Adjusting Ring in slot in headlamp mounting ring.
Page 539 Sec. 12 G M C S E R V I C E M A N U A L Page 528 CHASSIS ELECTRICAL A N D INSTRUMENTS Figure 15— Dom e Light (Tilt Cab M odel) (Typical) with a jumper wire, then place the ignition or con trol switch in the "ON”...
Page 540 Sec. 12 G M C S E R V I C E M A N U A L Page 529 CHASSIS ELECTRICAL A N D INSTRUMENTS N O . 7 N O . 6 N O . 1 D O M ELIG H T Figure 16—...
Page 541 Sec. 12 G M C S E R V I C E M A N U A L Page 530 CHASSIS ELECTRICAL A N D INSTRUMENTS switch, then position switch and mounting bracket DIRECTIONAL LAMP LENS on cab floor panel and secure. On Tilt Cab Models - tilt cab forward and in...
Page 542 G M C S E R V I C E M A N U A L ______________________ Page%3i CHASSIS ELECTRICAL A N D INSTRUMENTS from flasher unit through switch, then to right- hand signal. The same procedure applies to the left-hand signal, except that lever is in the down position and a different set of contacts are engaged in switch assembly.
Page 543 Sec. 12 G M C S E R V I C E M A N U A L Page 532 CHASSIS ELECTRICAL A N D INSTRUMENTS when on-the-road disability occurs. This system is DIRECTIONAL SIG N A L fed from the battery and can be operated regard C O N TRO L ASSEMBLY SWITCH TO le ss of ignition or control switch position.
Page 544 Sec. 12 G M C S E R V I C E M A N U A L Page 533 CHASSIS ELECTRICAL A N D INSTRUMENTS circuit referring to "Wiring Diagram" in applic If directional tell-tale on instrument panel does not flash in either direction, check for the able "Wiring Diagrams"...
Page 545 Sec. 12 ______________________ G M C S E R V I C E M A N U A L Page 534 CHASSIS ELECTRICAL A N D INSTRUMENTS KEEP ALL WIRING CONNECTIONS CLEAN AND TIGHT DO NOT REPLACE FUSIBLE LINKS WITH WIRE OF LARGER GAUGE OR LENGTH DISCONNECT NEGATIVE BATTERY CABLE FROM...
Page 546 Sec. 13 G M C S E R V I C E M A N U A L Page 535 SECTION 13 H adLcita>i A S u A ae ^ la n k Subject Page No. Description ..............Maintenance ..............Radiator Mountings .............
Page 547 Sec. 13 G M C S E R V I C E M A N U A L Page 536 RADIATOR A N D SURGE TANK RADIATOR REPLACEMENT Check filler cap seals for evidence of cracking or separation. Replace as required. To assist in maintaining efficient heat d issi...
Page 548 Sec. 13 G M C S E R V I C E M A N U A L Page 537 RADIATOR A N D SURGE TANK Radiator Rubber Bushing Support M ounting Bolt W ashers Control Island M o u n tin g Cotter Pin Frame Bracket Bracket...
Page 549 Sec. 13 G M C S E R V I C E M A N U A L Page 538 RADIATOR A N D SURGE TANK ing. Tank serves as a coolant reservoir for the C a p Unit radiator core which is mounted at front of engine. Hoses and pipes connect tank to radiator and water pump.
Page 550 Sec. 13 G M C S E R V I C E M A N U A L Page 539 RADIATOR A N D SURGE TANK After thawing, refill system with a higher concen 4. Do not remove radiator filler cap when en gine is hot.
Page 551 Sec. 13 G M C S E R V I C E M A N U A L Page 540 RADIATOR A N D SURGE TANK Always use coolant containing rust and cor rosion inhibitor compounds. When vehicle is operated in freezing weather, protect cooling system by use of permanent-type antifreeze.
Page 552 These tools, or their equivalent, are necessary and are recommended to readily and efficiently accomplish certain service operations. The tools, however, are not supplied by GMC Truck and Coach Division. Information regarding availability of these tools can be obtained from the Zone Office or from the Technical Publica...
Page 553 G M C S E R V I C E M A N U A L Page 542 SPECIAL TOOLS SEC TIO N 6M - G ASOLINE ENGINE SECTIO N 7D - C LU TCH CO NTROLS F U E L SYST EM Tool No.
Page 554 G M C S E R V I C E M A N U A L Page 543 INDEX Subject Page No. Subject Page No. (Cont'd.) Brakes Accelerator Linkage A i r ............... D iesel Engines ..........H ydraulic............Gasoline E n g in e s ..........Parking ...............
Page 555 G M C S E R V I C E M A N U A L Page 544 Subject Page No. Subject Page No. --------- (Cont'd.) Ignition S y stem ............Engines, Gasoline Instruments and G a u g e s........Maintenance ............
Page 556 G M C S E R V I C E M A N U A L Page 545 Subject Page No. Subject Page (Cont'd.) S (Cont’d.) Trailer Brake Controls ........Shoes, Brake Transm issions ............... Control L inkage..........H y d r a u lic ............. Service Operations ........

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