Chevrolet HM80 Series Service Manual
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Chevrolet HM80 Series Service Manual

Chevrolet HM80 Series Service Manual

1972 heavy duty truck
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HEAVY DUTY TRUCK
SUPPLEMENT

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Summary of Contents for Chevrolet HM80 Series

  • Page 1 HEAVY DUTY TRUCK SUPPLEMENT...
  • Page 2 SHEET METAL CHASSIS ELECTRICAL AND INSTRUMENTS RADIATOR AND SURGE TANK CHEVROLET MOTOR DIVISION SPECIAL TOOLS £ G e n e ra l M otors C o rporation D ETR O IT, M IC H IG A N © 1972 Printed in U .S .A .

  • Page 3: Table Of Contents

    Fuel Tank and E xhaust............... Steering System ................Wheels and T ir e s................Sheet M etal................... Chassis Electrical and Instruments .......... Radiator and Surge Tank............Special T o o ls................. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 4 7452E RT910, RT09513 1514-2** R170 14-2** JB90 8V-903 F120 SLH D RT910 JC90 NHCT270 NTC335 14-2** m - 2 * * F090 F I 20, FL901 SLH D SQHD RT910 RT09513 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 5 N H230 14-2 F120 DN90 SQHD 14-2** RT01213 SQHD 12V-71 m - 2 * * F120 DP90 — ♦Equipped with Ceram etalix Clutch Discs. ** S p ic e r Clutch. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL' SUPPLEMENT...
  • Page 6 VEHICLE MODEL IDENTIFICATION In order that a vehicle may be specifically identified as to manufacturer, chassis type, engine type, GVW range, cab/axle dimension, continuous model, plant code, and sequential number, refer to the chart below. CHASSIS T Y P E SYM BOL C - C o n v .
  • Page 7 6,000 m ile in tervals. LUBRICATION CHARTS DRAINING AND FILLING When new or after overhaul, drain fluid and A ll lube charts have been updated. change filte r elem ent after 3000 m iles; thereafter CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 8: Lubrication

    Sec. 0-2 LUBRICATION Figure 1 —Lubrication Chart (Conventional C ab M o d e ls)
  • Page 9 No lube required on sid e term inal type battery. Or every 30 days, w hichever o ccu rs fir st. Or every 4 months, w hichever o ccu rs fir st. (k ) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 10 S ec. 0 -4 LUBRICATION CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 11 , then move a c c e ss cover to expose g rease fitting.) (f) Optional oil lubricated front wheel bearings u se "GO” type o il. (g) No periodic servicin g with oil lubricated bearings (Stemco se a ls). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 12 Sec. 0 -6 LUBRICATION CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 13 (g) No periodic serv icin g with oil lubricated b ear­ lubricate every 6,000 m iles or 60 days, which­ ings (Stemco se a ls). ever o ccu rs fir st. (d) If used. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 14 Sec. 0-8 LUBRICATION CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 15 (c) When "MPG" M ulti-P urpose G rease is sp ecified lubricate every 6,000 m iles or 60 days, whichever o ccu rs fir s t. (d) If used. (e) 12,000 m ile s under se v e r e operation (change filte r when changing o il). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 16 (b) Or every 6 months, w hichever o ccu rs fir st, (c) If used , (d) No periodic serv icin g with oil lubricated bearings (Stemco se a ls). Figure 5 —Lubrication Chart Tandem Bevel (SLHD, SQHD, SSHD, 3 0 34DS, and 34D3) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 17 11 Tachom eter Adapter ( b ) ......(c) Gas Engine Only. (b) If used. (a) R eplace lubricator at 24,000 m ile in tervals Figure 6 —Engine Lubrication Chart (Except Cumm ins) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 18 1 engine o ils MS-DM (SE/CC New A .P .I. D e sig ­ Fluid in autom atic tra n sm issio n s. nation) , with a history of satisfa cto ry perform ance CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 19 3. R aise locking button to unlocked position. 4. Actuate outside push button to open the Figure 1 —Checking Striker Boll A djustm ent door. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 20: Cab And Body Mountings

    If cab is T-8799 raised too high, damage to vehicle wiring, operating controls, and lines may occur. 3— Cob Figure Front M ount (with O ne Piece Cushion) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 21 NOTE: Curved windshield wiper blade is de­ signed to accept a r efill in sert for se r v ic e r e ­ Figure 5 —Dual W iper Control V a lv e Schematic placem ent. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 22 ELBOW WITH TUBING INSERT NYLON FERRULE vlUT NYLON TUBING Figure 7 —W iper M otor A ir Line Connection ITypical) Figure 8 —W iper Blade Replacem ent CHEVROLET SERIES 70-90 HEAVY DOTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 23 17 Spacer 10 B earing T-8269 24 Gear Rack A ssy . 18 Nut 11 Spacer Figure 9 —A ir O perated W in dsh ield W iper (Series 90 Conventional Cab) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 24 (10). 4. Gear rack (24) can now be withdrawn from NOTE: When installing gear (12) into gear cylin der body (13). rack (24) make sure that the teeth match the rack CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 25 A ir line plugged. Valve defective or e. Wiper w ill not run. broken. Gear se c to r broken. Wiper valve or piston gummed up due to foreign d eposits, due to dirty air line. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 26 ALWAYS WEAR HEAVY TYPE GLOVES TO PREVENT INJURY WHEN HANDLING GLASS. IMPORTANT NEVER SLEEP IN CAB UNLESS ADEQUATE VENTILATION IS PROVIDED. IMPORTANT DO NOT DRILL ADDITIONAL HOLES IN FRAME. DO NOT WELD HEAT TREATED FRAMES. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 27 (R efer to "G eneral W elding In­ stru ction s” in the Heavy Duty Truck Service Manual ST 135-70.) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 28: Frame

    Type or E le c tro d e ..................E-7011 E-11016 E-7016 E-11018 E-7018 SIDE RAIL MATERIAL IDENTIFICATION (Location— Centerline of Front Axle) SAE1023 SAE950 High Performance CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 29 ♦Regardless of m axim um turning angles specified, ad justm ent of stop sc with any c h a ssis components. A bent steering arm w ill cau se im proper turning angles. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 30 15 Tie Rod End A ssy. Cap Screw 16 Plug Retainer Dust Cap 17 Expansion Plug Kingpin Nut 18 Kingpin Bushing Cotter Pin (Lower) T-8795 Figure 3 —Steering Knuckle IF 120 A xle) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 31 13 Thrust B earing 14 Seal 15 Tie Rod End A ssem bly 16 R etainer 17 Expansion Plug 18 Steering Knuckle Bushing (Lower) Figure 5 —Steering Knuckle ( F I61 A xle) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 32 The front wheel 8. At bottom of knuckle, in stall expansion plug bearing adjustment procedure is the sam e as ex­ and plug lock ring. plained for the F I 20 axle. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 33 1/8-inch or no more than 3/16-inch. With key installed, stake around draw key hole as shown . T -9051 Figure 9 —K ing Pin D raw Keys IF 161 and F901 Axles) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 34 Screw ......5 - 6 Ft. Lbs. 5 - 6 Ft. Lbs. 5 - 6 Ft. Lbs. — — * Burnish after Installation CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 35 Refer to "Speci­ vicinity of the spring center bolt. fications" for shock absorber nut torque. NUT TORQ UE 35-45 FT.-LBS. FRONT MOUNTING—MODELS WM80, TM80 & TE90 Figure JO—Front Spring Front M ountings (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 36 16-18 FT. LBS. TORQUE SPRING PIN SPRING PIN BOLT BOLT SPRING SPRING WASHER WASHER REAR MOUNTING-MODEL RM80 REAR MOUNTING—MODELS TM80, TE90 & WM80 T-8176 Figure 11 —Front Spring Rear M ountings (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 37 FL901 A xle Hubs and B ea r­ ings (fig. 12) and o il lubricated front wheel bearings (fig. 13). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 38 V eh icles with s e a ls should be in a lev el Figure 13— O il Levels (Oil Lubricated Type Bearings) position for checking or adding o il. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 39 Cap S crew — 5/i6'-24............11-18 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 40 LOW range. Apply parking brake, p lace tran sm ission in neutral and shut off engine. When leaving the vehicle parked or unattended the previous instructions must be followed. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 41 11 Stud 5 Top Pad to Spring 12 Thrust Washer Saddle B olts 13 Bushing 6 Lock Nut Figure 2 —Section Through Spring, Sa d d le, and Beam (Hendrickson RT) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 42 NOTE: A ll suspension rep airs should be made n ec essa ry , tag bracket "Front” or "Rear" and on lev e l surface. sc rib e between bracket and control arm . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 43 Radius rods are mounted on rubber bushings and held in place at forw ard side of axle housing by the require no lubrication. sprin g sea t, U -bolt and bottom p late. A rubber CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 44 If bushing 3. Insert pin in shackle, aligning grooves in is worn e x c e ssiv e ly , rep lace as d irected . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 45 1 and No. 2 le a v e s on both the main and auxiliary sp a cer, then rem ove spring assem b ly. sp rin gs can be replaced. If other than the No. 1 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 46 (fig. 7). P in s are secu red with nuts, w ash ers, and step s 1 through 4 under "Installation at R ear End." a re locked to radius rod by draw keys in serted CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 47: Rear Suspension

    Torque Rod Ball S t u d ........CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 48 17 Nylon Thrust W asher 8 W asher (Cork) 9 W asher (Steel) SERIES 1700 SERIES 1800 T-8225 Figure 1 —Typical Propeller Shaft with Type 1700 or 1800 Series Universal Joint CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 49 9 Lock W asher 6 T ie Bar 2 Lubrication Fitting 3 Special Cap Screw Figure 2—Type 58 WB and 6 8 WB U niversal Joints Showing High and Delta Wing Bearings CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 50 (” CL 385V Main Trans. SP 6852K Aux. Trans. MT 41 Main Trans. SP 8341C Aux. Trans. SP 7041 Aux. Trans. Aux. Trans. SP 6852S MT 42 Main Trans. SP 7452E Aux. Trans. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 51 Make certain push rod is aligned properly and have push rod too short than for it to be too long. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 52: Brakes

    CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 53 W ITH D RAW IN G MANDREL FROM BARB BO DY the exhaust port upward and holding it until draining i s com pleted. Figure 1 — Nylon Tubing Assem bly CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 54 3 R o ller 7 C otter Pin 4 W edge R etainer 8 W edge W asher Figure 4—W edge and Roller A ssem bly Figure 5— Installing W edge Assem bly CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 55 (fig. 8), rem ove two scr e w s and lift cover and NAIL SEAL COVER FILTER SPRING ' RETAINER ; SCREW AND LOCK W ASHER ■ T-6926 Figure 8 —Filter Installed Figure 7 —Breather and Filter A ssem bly CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 56 Rem ove, disassem b le, clean, inspect, le-se t (1 ) W here more than one interval is given, operation to be performed at tim e of w hichever occurs first. (2 ) Determ ined by severity of service. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 57 JV 70, TE, MB, MC, JB , HC, HE, HH, HI, HN, JC, J E , JH , J l, JN , MH 90 and all 90 15x7 Wedge 15x7 RM-TM 80, TV 70 16-1/2x7 WM-HM 80, WV 70 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 58 The air co m p ressor is the source of supply for the veh icle braking sy stem . Faulty operation of the com p ressor w ill resu lt in im proper function of brakes. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 59 R eplace hose Rubber vent hose collapsed or plugged Engine requires m ajor overhaul Extrem e engine blow-by Figure 1 —PCV Valve Problem A n alysis Chart (Using A C Tester CT-31 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 60: Gasoline Engines

    A lso rem ove the crankcase ventilation valves which are screw ed a c c e sso r y drive b elts. into threaded ports in cylinder heads. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 61 9 Engine Front Cover 5 Installer Screw 10 Oil Seal 12,72 Figure 5 —Installing D am per on Crankshaft w ith Special Tool Set Figure 4 —C rankshaft D am per Retaining Parts (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 62 (8) and Rem ove engine o il pan as p reviou sly in­ float assem b ly (9) lo o sely to upper o il pan (2). structed. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 63 5. Install engine o il pan, following the in stru c­ tions previously given under "Engine Oil Pan R e­ Figure 9 —Rem oving Seal U pper H a lf From Block placem ent." CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 64 USE ENGINE OIL AS SPECIFIED IN LUBRICATION (SEC. 0) AND SERVICE CRANKCASE VENTILATION UNITS AND OIL FILTER REGULARLY. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 65 TORQUE (F T .-L B S.) ......... 130-135 NOTE: At engine idle speed with vacuum line disconnected and plugged. * No load speed is approxim ately 300 rpm higher than full load speed. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 66 Fuel Pump Mounting B olts 5 / 1 6 " ....................12-17 Fuel Pump Mounting B olts 3/8" ....................20-25 Oil Pump Cover B olts ........................8-15 * Lubricate threads and bolt head with S.A .E. # 10 Engine Oil. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 67 To provide a m ore accurate alignment of the ing. T his change was made to meet Federal ex­ cylinder head to the lin er bore of the cylinder haust sm oke em ission requirem ents that apply to CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 68 The current governor is a sin gle weight type used. and provides an id le speed range of 500 to 1800 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 69 6-71 S e r ie s d iesel engine. This is not n ecessary Tighten lock nut to retain the adjustm ent. Back out on V engines. the buffer screw after the idle speed is established, CHEVROLET s W s 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 70 "NO-FUEL" position. Install cover screw s and sem bly to obtain the d esired idle speed (550 rpm w a sh ers. minimum) IN to in crea se or OUT to d e crea se. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 71 Manual ST135-70 w ill apply with the addition of m em bers. the follow ing information: CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 72 CA M S H A FT G EA R B A LA N CE SHAFT G E A R Figure 5—6-7! Engine Timing Figure 6—V -7? Engine Timing CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 73 Provide an exten­ NOTE: Make certain that the crankshaft pulley sion for the spindle of the indicator. The extension CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 74 25 pounds w ill com p ress the spring to a length of A ll Tune-Up O perations and Adjustm ents Should B e P erform ed C arefully and In P roper Sequence CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 75 3. Check the valve clearan ce 0.024" for the Figure 10 —Test Panel (Fabricate Locally) 53 S e r ie s engine and 0.014" for 71 S e ries engine CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT .
  • Page 76 NOTE: Do not crank the engine with the sta r t­ inate m isfirin g, check the com pression p r e ssu r e s. ing m otor to check the com pression p r e ssu r e . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 77 Figure 15—Inspection for Broken or Stuck Piston Rings (Typical) the piston. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 78 AS POSSIBLE, to avoid e x c e ssiv e deposit form ­ indicates air in the sy stem , or a restriction in the ation and prem ature w ear. fuel sy stem . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 79 Clogged prim ary or secondary fuel filte r and the lin er into the crankcase, m ost of which is elem ent. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 80 R efer to ENGINE COOLING SYSTEM (SEC. 1. Worn or im proper seating of blower se a ls. 6K) of this supplem ent for cooling sy ste m checks. 2. D efective blow er. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 81 V-71 11.5 blow er a ir intake assem b ly and drill and tap a hole CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 82 NOTE: Due to variations in exhaust sy stem s haust manifold companion flange and tapping a 1/8" (horizontal or v ertical stacks) the above chart is pipe thread. typical. Check the readings obtained at various speeds CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 83 If leak s are indicated, rep lace the co re. sy ste m is a s follow s: CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 84 . Cylinder Head may be checked a s p revi­ B e su re a ll foreign m aterial is rem oved from ously-d escribed . around the studs. CHEVROLET SERIES 70*90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 85 Threads and bolt heads coated with International Compound #2 (Part No. 5198563). ** With engine running at 600 rpm. Variation between cylinders not to exceed 25 p si. *** U se injector tim ing gauge No. J-1853. FRONT CHEVROLET SERIES 70-90 ^ V Y °U TY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 86 C Y L IN D E R C O M P R E SS IO N (M in .)......515 P S I* * FRONT FRONT CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 87 (at Crossm em ber) 7 P late Cooler H ose Support 5 Engine Mounting T-9063 T-9065 Figure 3 —Front Dual C om pressive M ount Figure 1 —Front Com pressive M ount CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 88: Engine Mountings

    2 Bolts with Plain 6 Mounting Bolts W ashers 7 Plate 3 Mounting Bolt Nuts 8 Fram e Member T-9067 Figure 5 —Front Fabreeka M ount Figure 7 —Front Trunnion M ount CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 89 5 Spacer Casting -9056 upper cushion; amd provide safety block­ ing to prevent tipping and possible damage to front mountings. Figure 9 —Rear Saddle M ount CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 90 Sec. 6D -84 ENGINE MOUNTINGS torque:- 1/2" 55-65 ft.-lbs. 5/8" 130-140 ft.-lbs. 3 /4 " 180-200 ft.-lbs. torque: 1/2" 55-65 ft.-lbs. 9/16" 60-70 ft.-lbs. V IEW A —TYPICAL REAR M OUNTIN G WITH FULLER T R A N S. V IEW B —TYPICAL REAR M O U N TIN G WITH SPICER T R A N S. 1 Cap Bolt and Washer 5 Bracket (at Trans.) 9 Frame Bracket...
  • Page 91 3/4" 180-200 - 10-16 240-270 400-430 210-230 7/8" 9-14 700-730 320-350 1" 325-380 8-14 * 40 - 50 T-9074 ** 55 - 65 Torque for aluminum casting. *** 60 - 70 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 92 Inspect engine front and rear mountings as part of regular engine m aintenance program . Be su re to keep bolts and nuts tightened to torque values sp ecified on chart. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 93 . Figure I— Typical Use of Cooling System Tester c . The indicator hand on gauge dial should CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 94: Engine Cooling System

    C apacities Chart" at the end of this section for are or are not expected, cooling sy ste m protection sy ste m capacities. should be m aintained at le a st to 0 ° F ., to provide CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 95 . V-BELT TENSION Fan belt tension on v eh icles equipped with Figure 4 —Thermostat Installation (12V-71 Diesel Engine) V -b elts should be adjusted to 120-130 pounds on CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 96 (8). Tighten bolts to 170 to 180 foot-pounds torque. REMOVAL 2. P la ce bracket assem b ly (9) including pulley 1. Loosen the generator and/or air conditioner (1) at bracket (7) and in stall adjusting bolt (5) with CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 97 If the bearings are to be bracket assem b ly must be used. Figure 6 —Fan Support, Pulley, and Fan I I 2 V-71 Diesel Engine) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 98 (1) to shaft with nut (2). Tighten nut to 100 to 110 foot-pounds torque. Figure 7—Fan Shaft and Housing A ssem bly (KM 80) 5. At opposite end of shaft, p lace drive key CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 99 NOTE: DO NOT drill or ream the dowel hole bly of this pump is the sam e as covered in S ervice in the pump body m ore than n ecessa ry . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 100 Cu m m in s D iesel En g in e s ..........205 °F . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 101 When r e s tr ic ­ tion is higher than 25 inches of water the elem ent should be cleaned or replaced. Figure 1 —A ir Cleaner (Some DH and FH M odelsI CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 102 D -1400. NOTE: To retain high engine efficiency and extend engine life , it is m ost important that air cleaner elem ents are serviced at recom m ended in tervals. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 103 T hese p la stic caps are not to be re ­ p la stic cap, a s shown. moved u n less made n ecessa ry by som e major CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 104 FAST IDLE SCREW THROTTLE LEVER VIEW C Figure 2 -B en d ix-Stro m b erg Carburetor (W W C Series) Figure 4 —Installing Plastic C aps (W W C Series) CHEVROLET SERIES 70 90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 105 6 3 7 - V 8 ......5° BTDC 7. R eset the engine idle speed as directed in Reconnect vacuum advance hose. Step 4. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 106 U se bending wrench until the face of the plunger hex contacting tool as illu strated in figure 7. Figure 7 —Typical Use o f Bending Tool to Set Float Level CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 107 Accelerator Pump T r a v e l..............‘ Carburetors Part No. 687115, 687116, 690120 Main Metering Jet is 0.061. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 108 Location..............Carburetor Throttle Body Note: Refer to GASOLINE ENGINES (sec. 6A) for spinner valve adjustment procedure. It is most important to perform Carburetor Idle and Mixture Adjustment as directed in this section. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 109 "C." Install w asher and lock pin on 3. In so m e c a s e s it may be n ecessa ry to ad­ trunnion "A." just rod end a ssem b ly "D" in front. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 110 "A.” Tighten lock nut, then in stall pull NOTE: Rand throttle must be in "OFF" p o si­ back spring "E." tion. Figure 3 —Accelerator Linkage (HH and JH M odels) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 111 71 D ie s e l engines and is de­ scrib ed in ST135-70 Service Manual, page 6M -22. Figure 5 —Alum inum Tilt Cab Linkage (Typical) Figure 6 —12V-71 Em ergency Stop Linkage CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 112 It is important that extrem e care be ex ercised in the handling and storage of d ie sel fuel oil, as absolute clea n lin ess is e ssen tia l to satisfactory engine operation. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 113 NOTE: A protractor can be used for this s e t ­ dim ension from floor to head of bolt as shown. ting. R em ove spring " F .” Figure 1 —Accelerator Linkage (JB M odels) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 114 "A" by pushing move rod "E" at lev er "D." Make sure a c c e le r - a ccelera to r rod "F" rearw ard. Adjust slip joint CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 115 C um m ins D ie s e l Engine r e fe r to "CUMMINS OPERATION AND MAINTEN­ ANCE MANUAL." CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 116: Engine Fuel System

    6. Super-charged air co m p ressor (when used), run engine at idle when starting to build air p r e ssu re . (Super-charged air co m p ressors operate under heavier bearing load.) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 117 TENSION ADJUSTMENT Except 283480 D rive belt must be kept at proper tension. A Model 2,83480 276558 lo o se or broken b elt w ill affect operation of the CHEVROLET SERIES 70 90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 118: Air Compressor And Governor

    281415 Belt Paper HV, JV 280095 12 Water Gear Foam 280368 Water Gear Paper 90 SERIES DH, FH 282013 Water Gear None 14'/2 Dl, FI 282011 Water Gear None 14 V CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 119 D B /D Q /D H /D P /F B /F C /F H 9 0 (Four B a t t e r i e s ) ....1980718 7DR-200 (Cont’d) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 120 3. Attach one end of one jumper cable to the acid on them. Install vent caps on both the booster p o sitiv e term inal of the booster battery (identified and the discharged battery. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 121 Sec. 6Y-115 BATTERY BATTERY TEST PROCEDURE NOTE: Chart No. 1 is in Specifications T 803i CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 122 D B /D C /D H /D N /F B /F C /F H /F N 9 0 ..........1114143 OPTIONAL PART NO. HM /JM /RM /TM 80 (With 478M Engine) ........1107586 H I/J I/D I/F I 9 0 ..................1114161 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 123 Figure 3 —Starter Autom atic D isengagem ent and Lock-Out (Series JB /M B /M C 9 0) (Typical) m agnetic sw itch. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 124 ”R" term inal w ill flow to ground through volt­ ing step s to perform the fr e e speed check. R efer age sen sin g relay operating coil causing norm ally to figure 5 for te st connections. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 125 Cummins Diesel Engine Models ...........Bolt 50-60 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 126: Engine Electrical

    Set with vacuum advance line disconnected and plugged. Satisfactory Range. When adjusting set to 30 degrees. (Gives 0.016 point opening). Reconnect hose to opposite side of vacuum unit & adjust cam angle w -vac. full retard. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 127 7 5 -A M P .— D B /D C /D N /F B /F C /F N 9 0 ............1117225 Integral 7 5 -A M P .— D H /D I/D P /F H /F I90 ............1117231 Integral * R equires 1115827 F ield Relay on RM80. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 128 S f c - R <X 'T > -I I6N . COIL O--—r WITH 1119515 REGULATOR Figure 1 —Schematic Diagram of A . Charging Circuit w ith Two-Unit Type Regulator tTypical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 129 Figure 4 —Schematic Diagram o f A-C. C harging Circuit w ith Full Transistor Regulator Figure 3 —Schem atic Diagram o f A .C. C harging and 1115841 Field Relay (Typical) Circuit w ith 1116378 Regulator (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 130 Figure 6 —Schematic Diagram of A .C . Charging Circuit w ith 1119507 Regulator an d 1115827 Field Relay centric with the rotor shaft. A sp ecial constant CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 131 -s e t value by tor (fig. 7). On 62-amp generating sy ste m s (except controlling the generator field current. The diodes, CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 132 A sm all a defective stator. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 133 3. A defective diode or stator resulting in an belt should be adjusted to 84-94 pounds on a new e le c tr ica l unbalance. belt or 64-74 pounds on a used belt. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 134 (fig. 10), connect jumper lead between w iring har­ n ess connector "F” term inal and No. 4 term inal as Figure 11 —Checking Indicator Lamp W iring shown in figure 11. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 135 3. If indicator lamp does not illum inate with s e r t a voltm eter te st prod into the wiring ignition or control sw itch on and engine not running, harness connector No. 4 term inal. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 136 Check w iring h arn ess for grounds. Make continuity checks a s follow s with the ignition 7 2—Connections Figure fo r Testing Generator Output 719507 or 7 7 19575 (w ith 1 RegulatorI sw itch on: CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 137 Check battery a s explained under "Battery term in al and No. 3 term inal a s shown in figure 13. T est Procedure" in "BATTERY" sectio n previously. 4. Connect negative battery cable to battery. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 138 REGULATOR CIRCUIT TEST (WITH 1116374 OR 1116378 REGULATOR) Since m ost charging sy stem troubles show up Figure 15—Connections for Testing 1116374 or 1116378 Regulator (Typical) as an undercharged or overcharged battery, the CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 139 NOTE: V oltm eter p o sitiv e lead is connected of reasonable length. to regulator mounting bolt and voltm eter negative b. To low er the voltage setting, turn slotted lead is connected to battery negative post with CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 140 VIEW D -C H EC K IN G FOR EXCESSIVE CIRCUIT USING OHMMETER RESISTANCE -1547 Figure 17—Using A dap ter (J - 2 1600) to Check Circuit w ith 9 0 0 05 9 0 Type Regulator CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 141 D isconnect lead after 60 in View C, figure 17. secon d s to prevent overheating. c . If ohm m eter reads high, there is an open, CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 142 Adjust if n ecessa ry . Figure 18—A d ju stin g V oltage Setting Always cy cle the regulator (Step 7) before reading ITwo-Unit Type Regulator) ITypical) the final voltage setting. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 143 1. Attach generator to mounting bracket and in sta ll adjusting arm clamp bolt. grounded while being disconnected. 2. P lace drive belt(s) over generator drive CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 144 NOTE: Condenser lead is connected inside the generator. Leave condenser with generator. REMOVAL 4. R em ove brush holder, brushes, and brush 1. D isconnect negative battery cable. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 145 No. 6 No. 3 No. 5 FIELD RELAY ADJUSTMENT Figure 2 4 —Regulator w ith Cover Rem oved 1. R eferring to figure 21, in sert an 0.030-inch CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 146 No 7 BACK BIAS DIODE TR A N S ISTO R FIELD DISCHARGE (M OUNTED ON REVERSE SIDE) DIODE Figure 2 6 —Com ponent Parts o f Panel Board A ssem bly CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 147 (PART 10, Fig. 27) R eplace the diode if both readings are zero, if both readings a re infinite, or if both readings are identical. Figure 2 9 —Checking Transistors for Shorts CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 148 C H E C K B A T T E R Y 1 -5 5 9 4 Figure 31 —Field Relay Unit Check Figure 3 3 —Regulator w ith Bottom Plate Rem oved CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 149 "Specifications" replace the relay. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 150 SUPPRESSION DIODE (D4), (PART C, Fig. 36) To check the regulator (fig. 32) for defective If the two readings are identical, the diode is com ponents, proceed as follow s: faulty. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 151 Step 3, are zero or very low and identical, if both readings a re infinite or nearly infinite, the the tran sistor is shorted. r e sis to r is open. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 152 Voltage C h a r t............... No. 1 No. 1 (a ) Tolerance Plus or M inus 2 0 % (b) Make Final Adjustm ent a s Per Text CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 153 Sealing Voltage R a n g e ............above closing CHEVROLET SERIES 70*90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 154 Bolt 25-30 HI/Jt/MI-90................35-45 Bolt H N /JN -90................With 62-Amp. Generator (Model 1117756) Bolt 25-30 HI/JI/DI/FI-90................35-45 Bolt DC/DN/FC/FN-90..............40-50 DH/FH-90................Bolt 40-50 Bolt With 62-Amp. Generator (1117781 or 1118887)....... CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 155 A capacitor, or condenser, mounted in the end fram e, protects the rectifier Figure 1 —Generator and Regulator Circuitry (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 156 5000 2500 Load Battery With Carbon P ile to Obtain M axim um Output. Rated Hot O utp u t .......... (b ) At M axim um O perating Speed. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 157 INJURY COULD R E S U L T TO V E H IC L E allow tran sm ission to upshift and should allow OR PER SO N N EL. downshifts at the highest rpm p o ssib le. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 158 (O) is accom plished 70 (se e fig. 1): by relocating the iwo jam nuts located on the de­ a. D isconnect throttle return spring (Q). tent button assem b ly. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 159 11. D isconnect rod (H) from le v er (D) and loosen nut (F). Figure 3 —Installing TV Linkage A djustm ent G auge 12. Insert %-inch diam eter rod (C) through CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 160 (2600 rpm ). If upshifts do not occur at sp ecified rpm adjust as follow s: Figure 5 —Position of TV Lever a t Idle a. To ra ise shift point, shorten TV rod (L) by CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 161 (E) is com pressed (THRU-DETENT). Ample should be aligned with the "IDLE" lin e on gauge as clea ra n ce m ust e x ist between the pedal and floor CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 162 (3400 rpm with 401M engine). If upshifts do 3. Note that gauge is in stalled on manual se le c to r nut. not occur at sp ecified rpm adjust a s follows: CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 163 (525 rpm). Road te st or (D) until contact is made with stop bolt (C) and dynam om eter te st veh icle to check for full load CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 164 To low er shift point, lengthen shift cable upper portion of slo t contacts c le v is pin (M). Se­ (H) in the sam e manner as the preceding step. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 165 NOTE: AT540 tran sm ission replacem ent procedures a re found in "TRANSMISSION ON-VEHICLE SERVICE OPERATIONS” (SEC. 7B) follow ing in this supplem ent. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 166 With clutch housing-to-flyw heel housing bolts in stalled and engine rear mountings installed, 50-60 FT.-LBS. -»031 Figure 2—Transmission Rear Mounting (DP90) Figure 1—Shear Type Transm ission M ounting CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 167 If the reading is not between 57 sem bly between sp ecial w asher and rear mounting and 62 p si the valve should be replaced. bracket (lifting equipment removed) which should CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 168 Rem ove vent hose m ission enters pilot hole in center of flyw heel. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 169 - out from the vehicle. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 170 3. D isconnect shift control rods or cables m issio n mountings which vary due to different from the front of the tran sm ission . veh icle driveline configurations. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 171 70-80 FT. LBS. VIEW D-REAR MOUNT SPICER 8341 AUXILIARY TRANSMISSION VIEW F-FRONT MOUNTING VIEW E-FRONT MOUNT SPICER 8341 T-9029 Figure 1 “ ‘ A u x ilia ry Transm ission M ountings CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 172 LUBRICATION (SEC. 0) in the 1970 and output ends of the tra n sm issio n a s described Heavy Duty Truck S ervice Manual ST135-70. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 173 Figure I —Clutch Controls (H V , JV 7 0 and HM , Figure 2 —M echanical Clutch Controls (Series 90 Conv. Cab Except JB , M B , M C 90) JM 8 0 with 47 8 M Engine) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 174 A fter the internal 3. D isconnect clutch le v e r return spring from clutch adjustment has been perform ed, adjust the r e le a se lev er. external linkage as follows: CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 175 R em ove block from clutch pedal and check oper­ ation of clutch linkage. adjust the external linkage as follows: CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 176 Tighten upper lock nut against linkage due to worn bushings, sh afts, or linkage upper adjusting nut. a rm s. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 177 LUBRICATION (SEC. 0) of the 1970 Heavy Duty 8. Install inspection hole cover in low er p or­ tion of clutch housing. Truck S ervice Manual ST135-70, page 0 -1 9 . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 178 A ll inform ation in the 1970 Heavy Duty Truck S ervice Manual ST135-70 pertaining to "FRONT END DRIVE POWER TAKE-OFF” pages 7-67 and 7-68, is applicable to m odels JM80 and JI90 covered by this supplement. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 179 CH AIN SO LDERED TO BAR -----OR WRAPPED AROUND O PTIO N A L CO N STRUCTIO N T-7953 Figure 1— Safety C ap and Venf Check V alve Plug (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 180 Fuel Tpnk Mounting Bracket to Frame .(Bolt) (1/2 x 13). 65- 85 Ft. Lbs. (Nut) (5 /8 x 11). 90- 110 Ft. Lbs. (Bolt) (5 /8 x 11). 125- 145 Ft. Lbs. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 181 Exhaust sy stem perform ance com plaints such as e x c e ssiv e back p re ssu re or a malfunctioning gasoline engine exhaust control valve are usually noticeable by their effect on engine perform ance. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 182 IMPORTANT: Som e area s of the country require that an operating vehicle m eets a n o ise -m e te r test. For assurance of minimum exhaust sy stem n oise, u se C hevrolet Replacem ent parts or equivalent. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 183 Figure 2 —Steering Column and Shaft Com ponents (Conventional Cab M odels! (Typical) Figure 1 —Till Column Quick Release M echanism CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 184 IW A V . C R O S S G R O O V E T-9104 Figure 4 —Steering G ear W orm shaft (Stub End) and Interm ediate Shaft Yoke and C/am p CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 185 -6476 Figure 8 —Steering Column Stop Clam p A djustm ent (Conv. C abl (Typical) Figure 6 —Flexib le Coupling Adjustm ent (Conv. C abI CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 186 568 D -7 3 ............Nut 250-300 ‘ Tighten to Specified Torque, Then Advance to Next Aligning Slot and Install New Cotter Pin. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 187: Steering System

    PARTS IN THAT THEY COULD AFFECT THE and blown cle a r . Tag all lin e s a n d h o sesfo r proper PERFORMANCE OF VITAL COMPONENTS AND relocation. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 188 14 Bearing Race - Sm all Plungers 15 Valve Spool Preload Spring TPM-7372 Figure 1 - 5 6 8 - D V Steering G ear H ydraulic V a lve Com ponents CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 189 PRELO A D % 335SS3^ ,1 5 SPRING T -7 8 4 0 Figure 2 —Pow er Steering G ear and Control V alve Type S68-D V (U sed on RM 8 0 M odelI CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 190 Pressure Relief Valve (Controlled F lo w )................1500 R.P.M. Pump Speed at 100 psi pressure CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 191 VANE HE-JE90 235 P VANE HH-JH90 VTM 27-60-45-10-MJ-L-1-12 VANE HI-JI90 235 P VANE MH90 VTM 27-50-30-10-MJ-L-1-12 VANE TE90 14-150 100-16 SLIPPER DC-DH-DN-FC-FH-FN90 235 P 137 VANE DI-FI90 235 P 132 VANE CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 192 EVERY 6,000 MILES OR FOUR MONTHS, WHICHEVER OCCURS FIRST. IF GM POWER STEERING FLUID IS NOT AVAILABLE, DEXRON AUTO­ MATIC TRANSMISSION FLUID MAY BE USED. CAUTION: DO NOT USE GM POWER STEERING FLUID IN AUTOMATIC TRANSMISSION. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 193 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 194: Wheels And Tires

    The rim a s shown in figure 6 has cracked Figure 4 —Budd Type D am aged Inner or Outer Cap Nuts from fatigue and overload. T his type of failu re is CHEVROLET SERIES 70-90 HEAVY DOTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 195 Figure 6 —Cracked or Corroded Rims CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 196 Figure 9 —Inflation of Tires fle x breaks; how ever, overloading exceed s a ll other CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 197 . c lo se r together in the front than they a re in the Cornering Wear — When a truck m akes an CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 198 %" ax le se r v ic e . sam e rollin g circu m ference. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 199 , la rg est to sm a lle st. t ir e s , may be used. 4. Mount the two la rg est tir e s on one sid e of CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 200 - the sum of the circu m ­ fer en ce s of the 4 tir e s for the front of the tandem CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 201 When a tube i s la rg er than the inside of the Figure 15—Proper Tube Inflation CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 202 - if inspection show s that it i s not damaged and can mounting different type rim s, refer to figu res 16, be u sed again. When the flap is again mounted, this 17, 18, and 19 for applicable type. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 203 , th en lif t o ff lock and side r in g s. Turn to recommended pressure. assembly over, unseat tire bead, stand tire up and remove rim base. T -8 3 0 7 Figure 16—M ounting and Dem ounting 3-Piece Convertible Rims CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 204 T - 8 3 0 8 Figure 17—M ounting and Demounting 2-Piece C onvertible and DT Rims CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 205 10" apart. Holding bead off. bead in w ell with foot, pull one tool toward center of rim. T-8309 Figure 18—M ounting an d Dem ounting 15° Drop-Center Tubeless Rims CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 206 DO NOT IN FLA TE IF SIDE RING DOES NOT MOVE FREELY. T-8317 Figure 19—M ounting and D em ounting RH5 Rims CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 207 -s id e rim im m ediately over the work beihg done on any tire su rfa ce. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 208 S ec. 10-p02 WHEEL$ AND TIRES Figure 2 0 —Rim and W heel Safety Precautions CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 209 R efer to page Do Not O verload T ir e s 205 for torque recom m endations. E nsure that the combination of load and veh icle CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 210 T his is good insurance for a val­ avoid running on a flat tir e , prevent underinflation uable investm ent. through regular checking of inflation p r e s s u r e s , and CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 211 5570 5860 6140 6420 6680 5620 5920 6200 6480 6740 7000 00-20 12.00-24 6660 6980 72807580 7880 6330 N O T E : Underlined Figures Indicate M axim um Recommended Load. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 212 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 213 Figure 2 —H ood H inge tHH, JH , HC, an d J C M odels) Figure 1— Typical Fender Brace (H and J M odels) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 214: Sheet M Etal

    If m aterials should com e in contact with skin, w ash thoroughly with soap and water as soon as p o ssib le. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 215 MAINTENANCE AND REPAIR TESTING CIRCUITS A careful study of the w iring diagram s should be made to determ ine the source and flow of cur­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 216: Chassis Electrical And Instruments

    90 tilt caty m odels is made through a m ale-fem ale being tightened, check to be su re gap between con­ type connector enclosed in rubber. n ectors is uniform. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 217 F rom A m m e t e r ....................18 B lk .-W h t. T r. To 4 -A m p . F u s e ................... .. 18 B lk . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 218 To T r a ile r I .C .C . M arker Lam p R ela y #3 T erm in a l , Dk. Grn. To R ear I. C. C. M arker L am ps ........Blk. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 219 F rom 8-W ay C onnector F ro m H azard W arning Switch . . . R ed To 6 - P o s t Junction B lock #4 Junction ..........12 R ed CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 220 To L ine C onnector To R ear I. C. C. M arker L am ps ..B lk. SPARE F rom 6 - P o s t Junction B lock #6 Junction ........Dk. B lue (Cont'd.) CHEVROLET SERIES 70 90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 221 , color, and pattern of the w ire which con­ the rear junction panel and a 16-term inal post nects to each term inal. junction panel is located on the front ele c tr ic a l CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 222 To 4 - Way C onnector To N eu tral Safety Sw itch ..W h t.-1 5 6 O p e n o p e n o p e n CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 223 By pushing r e se t button, circu its can be r e ­ Figure 4 —Front Chassis Junction (“ R” M odels) (Typical) energized. If breaker trip s instantly (button pops CHEVROLET SERIES 70 90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 224 An overload on the circu it, such as a short, stam ped on the ca se. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 225 No. 2 term inal of the a c c e sso r y feed the a c c e sso r y bus bar. relay when engine control sw itch is energized. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 226 A typical fuse block used on S eries 70 through TRICAL AND INSTRUMENTS (SEC. 12) in Service 90 tilt cab m odels is shown in figure 6, otherw ise Manual ST135-70. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 227 Be Figure 7 —Fusible Link an d Am m eter Fuses (Typical) Figure 8 —Electric Horn Control Circuit CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 228 LOW OIL T.T. (WHT. // RED TR.; YELL. / / BLUE TR.) LOW WATE R T.T. (WHT. // RED TR.; GRN & WHT. TR.) T-8784 Figure 9 —Connecfions af Rear o f Instrum ent Cluster (Co nv. Cob M odels) (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 229 16 R.H. Turn Signal T e ll-ta le MT-41 T ransm ission) Gauge, V oltm eter, or Am m eter T-8210 Figure 1J — Instrument Cluster (Series 70-90 Steel Tilt Cab M odels) ITypical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 230 12) pages 12-24 through 12-34 in S ervice Manual sa m e a s cbvered under "LIGHTING SYSTEM" in ST135-70 except as follow s: CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 231 70-90 tilt cab ing, then rem oving the len s. m odels. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 232 CHOKE RELAY (Series RM-80) Delco-Remy Make..................1116876 Model................... Air Gap at Core, Points Closed (In.)........... 0.011 Min. Point Opening (In.)..............0.025 Closing Voltage..............3.8-5.2 Opening Voltage..............0.6 Min. Sealing Voltage............... 0-0.2 Above Closing CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 233 S e c . 1 2 - 2 2 7 CHASSIS ELECTRICAL AND INSTRUMENTS SPECIFICATIONS (CONT.) CIRCUIT BREAKER TABULATION CIRCUIT BREAKERS NOTE: A 25-Amp. Circuit Breaker is installed inside the main light switch on all models covered by this supplement. CONVENTIONAL CAB MODELS AMPERAGE LOCATION...
  • Page 234 FUSIBLE LINKS Precise location of each fusible link used on vehicles covered by this supplement is shown in the tabulation on applicable wiring diagram in "Wiring Diagrams” in Manual Supplement ST-332-71. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 235 Figure 2 —Radiator M ounting (M odel JB , Figure 1 —Stabilizer Rod IM od els HC, JC , HH, and JH 9 0 ; DC, FC90 w ith NTC 335 Engine) M B 9 0; DB, FB90) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 236: Radiator And Surge Tank

    4. R em ove fan shroud attaching b olts, then 5. If veh icle is equipped with air conditioning lay shroud back over fan blade. or power steerin g, rem ove cooling c o ils from CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 237 5 Gasket 22 Engine Water Outlet 14 Shroud 6 Radiator Core Manifold 15 R.H. Side Assembly 7 Tie Rod Anchor T-9081 16 Insert 8 Washer Figure 4 —Perfex Type Radiator ITypical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 238 Figure 6 —Radiafor Shutter Air Cylinder point without p r e ssin g down on the cap. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...
  • Page 239 NOT u se G lycol Ether (Methoxy Propanol Type) in T oro-F low II Engines. 10. Drain and flush cooling sy ste m every other year, preferably at the begin­ ning or end of w inter operation. R efer to next page for "Specifications." CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

  • Page 240: Special T O O Ls

    D ie se l T est K its (Hand Tachom eter) B T -3 3 -7 3 -F V -B elt Tension Gauge J-9665 Guide Studs J-22506 D ie s e l T est K its (E lectric Tachom eter) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT...

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