Chevrolet 70 Series 1970 Service Manual
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Chevrolet 70 Series 1970 Service Manual

Chevrolet 70 Series 1970 Service Manual

Heavy duty truck
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Table of Contents

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CHEVROLET
HEAVY DUTY TR U C K
SERVICE MANUAL

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Summary of Contents for Chevrolet 70 Series 1970

  • Page 1 CHEVROLET HEAVY DUTY TR U C K SERVICE MANUAL...
  • Page 2 ENGINE MOUNTINGS This manual contains, Service procedures for maintenance adjustments, minor service operations, and replacement of components for Chevrolet Series 70, 80 and 90 Heavy Duty ENGINE COOLING SYSTEM Trucks. For disassembly and assembly of major components (overhaul operations) continue to refer to the 1969 Chevrolet Heavy Duty Truck Shop Manual.
  • Page 3 Chevrolet Truck. Every effort has been made to include timely and adequate information on the various units and systems used on Chevrolet Trucks.The general mainte­ nance and light repair procedures in the various manual sections are the result of extensive service experience.
  • Page 4 P arts Book. this manual. Many special equipment and acces­ sory items are available on these Chevrolet Trucks, however, these items are too numerous to permit SPECIAL TOOLS their coverage in this manual.
  • Page 5 N H C 2 5 0 14"-2 15!/2"-2 F090 F12 0 18221 1 9 12 1, 19221, N H 2 3 0 745 2E R T 9 1 0 , RT0913 R 170 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 6 R 170 m "-2 1 9 12 1, 19221, 74 5 2E R T 9 10 , RT0 913 FN90 NH C 250 NH 230 14"-2 F12 0 F lfiO 18221 R 170 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 7 O P T I O N o p t i o n D E S C R I P T I O N D E S C R I P T I O N CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 8 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 9 LUBRICATION 0-2 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 10 LUBRICATION 0-3 LUBRICATION DATA (CHART ON OPPOSITE PAGE) Item M iles (c) Item Rem arks Symbol 6,000 ..1 Spring Shackles & B rack ets ( d ) ....fittings each shackle 6,000 fitting each bracket ....
  • Page 11 LUBRICATION 0-4 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 12 (Loosen screw , then move a c c e s s co ver to expose g r ea se fitting.) (f) Optional o il lubricated front wheel bearings u se "GO" type o il. (g) No p eriodic serv icin g with oil lubricated bearings (Stem co se a ls). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 13 LUBRICATION 0-6 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 14 (e) A ir B rakes only. (c) When "MPG" M ulti-Purpose G rease is sp ecified lubricate every m ile s or 60 days, which­ 6 ,0 0 0 ever occu rs fir st. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 15 (a) Or once a yea r, w hichever occu rs fir st. (b) Or every m onths, w hichever occu rs fir st. (c) If used. Figure 4—Lubrication Chart Tandem Bevel (SLHD, SQHD, SSHD, 30DS, 34DS, and 34D3) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 16 1 f i t t i n g ............MPG (c) Gas Engine Only. (b) If u sed. (a) R eplace lubricator at 24,000 m ile in tervals. Figure 5—Engine Lubrication Chart (Except Cummins) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 17 (1) Add 2 pints at top of in te r -a x le differential SP8552/8554 ......cov er. SP8716 ......... (2) Add 2 pints at forw ard hole in top of differen­ T905 ........tia l c a rr ie r. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 18 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 19 Each v eh icle has a dipstick (Gasoline) (Typical) and o il fille r tube which is a c c e ss ib le by opening CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 20 LUBRICATION 0-13 the sm a ll door to the left of the "GMC" em blem on the front of the cab (fig. ). The main purpose of th is location i s to p erm it checking of o il le v e l and adding o il, if n e c e ssa r y , without having to tilt the cab.
  • Page 21 NOTE: Change engine o il and filte r in regular R em ove plug in cover and fill to le v e l of open­ m anner. ing with S.A .E . 10 engine o il. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 22 15 Inlet Check-Valve A ssem bly 16 P ack Support 17 Mounting B racket A ssem bly 18 O rifice Plug 19 B leed er H oles 20 Clamp Screw T-6698 Figure 11-Luber-Finer Unit CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 23 Ordinance Specification M IL-L-2105B and/or A .P .I. truck hypoid or bevel a x les, and tran sm issio n s, -G L -5 and indicated by the Symbol "MPO” on under maximum torque and speed conditions. It CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 24 -a x le differential housing. SPECIAL AXLE LUBRICATION Figure 15—Drain and Filler Plugs (Typical Transmission! Special lubrication i s required on a ll axles CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 25 T ran sm ission has one drain plug at bottom and rear w heel bearing lubrication. one fille r plug at left sid e (fig. 16) Figure 16—Drain and Filler Plugs (Fuller Transmission) Figure 17'—O il Lubricated Front Wheel Bearings CHEVROLET SEMES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 26 . 18) . It should not be Figure 18—Universal and Slip Joint Lubrication a ssu m ed that bearings a re lubricated u n le ss lu b ri­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 27 L ubricants Must B e Stored and D ispen sed in Such a Manner That They W ill B e Clean and F ree of Contamination, Due to D irt or Other Foreign M atter. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 28 R e ser v o ir shown in figure 21 is marked with an STEERING" (SEC. 9B) in th is manual for bleeding "OIL LEVEL" m ark. U se "Automatic T ran sm ission Fluid GM DEXRON ® ." the sy ste m . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 29 4. Add one quart of fluid when le v e l reaches the proper le v e l at all tim e s, oth erw ise insufficient "ADD" m ark. heat dissipation from tra n sm issio n oil w ill resu lt. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 30 Clutch Shift Fork B a ll Stud not exceed 6,000 m ile s. U se caution, when applying Steering Column Upper B earing lubricant, not to overlu b ricate or u se e x c e ssiv e CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 31 L ubricants Must B e Stored and D ispensed in Such a Manner That They W ill B e Clean and F ree of Contamination, Due to D irt or Other Foreign M atter. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 32: Table Of Contents

    Foot-O perated W indshield W ashers ............1-26 Lap B elt Maintenance ..................1-26 NOTE: R efer to re sp ec tiv e CAB section for a ll other inform ation. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 33: Exterior Maintenance

    , align door a s d e s­ section . cribed in applicable cab section . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 34: Cab Alignm Ent (Steel Constructed C A B S )

    Zinc coated m etals are a lso covered by these in ­ Thorough cleaning is e sse n tia l. A ll co rro ­ stru ction s. sion products, g r e a se , and other foreign m atter CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...

  • Page 35: Painting New Aluminum Parts And Repainting Old Parts

    5. B efore reinforcing any part of v eh icle, CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 36: Windshield Glass Replacement

    . If threads strip , u se existing holes and new g la ss, two at bottom and top and one at outer u se next la rg er s iz e sc r e w s. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 37 If a new in sert is being used, allow sufficient o v er­ lap to a ssu re a tight joint; then butt in sert into Figure 2 —Checking Glass Clearance (Steel Till Cab Models) w eatherstrip groove. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 38: R Ear Window G Lass Replacem Ent (All Except 9 0 )

    . Cut off end of in sert, allowing sufficient Tape ends of chalk string to inside of g la ss. overlap for a tight joint; then butt into groove. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 39: Door And Sleeper Compartment Ventilator Replacement (Series 90 Alum. Tilt Cab)

    Wiper A rm Adjustment (Fig. 5) Wiper arm can be repositioned on pivot shaft to provide proper sw eep a s follow s: Figure 5—Wiper Arm Installed (Steel Tilt Cab) Figure 6—Blade Angle Adjustment (Steel Tilt Cab) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 40 Figure 8 —Wiper Motor Installed (Series 70 Conventional Cab) which attach each tran sm issio n unit to underside CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL.
  • Page 41 Crank Arm Crank Arm Nut Retaining Retaining Ring Ring Transmission Motor Assembly Shaft Assembly DRIVE LINKAGE DISASSEMBLED DRIVE UNIT AND MOTOR ASSEMBLED r-03i Figure JO—Wiper Motor and Bracket Components (Steel Tilt Cab) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 42 Separate motor from mounting of the motor arm ature shaft, an interm ediate gear b racket. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 43 The shunt field current m ust then p a ss IMPORTANT: Wiper m ust operate in "LOW" through a r e s isto r located on the w iper term inal speed during parking cy cle. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 44 Check for lo o se w iper ground connection and/ No. 2 term inal (fig. 13). No voltage in d icates de­ or lo o se dash sw itch mounting. fe c tiv e w iring. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 45 B e su re brushes a re properly p ositioned in holders before arm ature com m utator Figure 16—End Play Wave Washer Installation protrudes between b ru sh es. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 46 (both le ft- and right-hand). in a p la stic cylinder housing. The piston type pump CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 47 ­ tions a re tight. sem b ly is defective and m ust be replaced . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 48 Wet the w indshield, then start w ipers in making su re that all mounting parts are tight and that a ir lin e s and line connections a re leak -p roof. m otion. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 49 Figure 23—Speed Balancing Valve ISeries 90 Conventional Cab) nut at the tra n sm issio n shaft, forw ard of cowl. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 50 R em ove valve head assem b ly as described 2. R em ove top co v er, View A, figure 24, by p reviou sly. rem oving four attaching sc r e w s. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 51 PISTON HEAD LOCKWASHER UNIT ASSEM. VIEW B PISTON ASSEMBLY FPD P V A LV E HEAD SHIM GEAR RACK VIEW C VIEW D ASSEMBLY T-4263 Figure 24—Air-Operated Wiper Motor (Series 90 Conventional Cab) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...

  • Page 52: Air-Operated Windshield Wipers (Series 90 Alum. Tilt Cab)

    While holding arm to prevent damage to 4. R everse rem oval procedure to in sta ll. linkage, rem ove crown nut (and w asher if used) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 53 SEPARATION OF MAJOR SUB-ASSEMBLIES R em ove retain er which attaches link to Figure 26—Wiper Arm Installation motor shaft assem b ly . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 54 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 55 R em ove d iscs sc r e w s. Tighten sc r e w s firm ly. Install O -rin gs on from end p la tes. adapters. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 56 O -rin g s. lin es from air junction fitting to main air supply is covered in "AIR BRAKES" (SEC. 5B) of this INSTALLATION manual. Install assem b led valve into console and con- CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 57: Foot-Operated Windshield Washers

    If n ecessa ry , to replace b elts or related at­ be used as sp ecified above to a ssu r e proper r e ­ taching p arts be su re to tighten lap belt anchor tention of th is part. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 58 The w indshield used on all conventional cab m odels covered in th is manual is of the on e-p iece type. Figure 1—Cob Welded Construction Figure 2—Cab Front Mounting CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 59 Figure 4-Full-W idth Seat Back Adjustment su rface of the m ateria l. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 60 2. With aid of an a s s is ta n t to support weight of door, rem ove th ree cap screw s which attach m ent. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 61 P erform clea ran c e adjustm ent at r e a r of door a s d irected la te r under "Door S trik e r." See "Door Figure 6—Door Clearances R ear Edge "In" o r "Out" A djustm ent.” CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 62 APPLY PAINT OR GREASE TO EDGE OF LOCK CAM ; SCRIBE HORIZONTAL LINE THROUGH CENTER OF LOCK “ V " STRIKER. BOLT MARK IN PAINT OR GREASE Figure 10—Striker Bolt Alignment Points CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 63 A fter obtaining p ro p e r fo re and aft adjustm ent, tighten bolt snug only at this tim e and then proceed Figure 12—Door Check Installed with the "S trik er Bolt Height A djustm ent." CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 64 Pull blocks from door to r e ­ ATTACHING BOLTS move. A flat-bladed tool, such as a putty knife, can be used for installing blocks in m anner shown Figure J 5—Door Handle Installation in figure 11. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 65 , then rotating re ta in e r as shown in figure 17. Remove shaft spring and button a ss e m ­ Figure 17—Disengaging Handle Spring Retainer bly with O -ring seal from handle. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 66 NOTE: F igure 20 illu s tra te s the com ponents the re ta in e r flange will not be v ertic al indoor slot. of the lock and rem ote control m echanism . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 67 "Door Lock Cylinder R eplacem ent." special tools. 6. At r e a r edge of door, rem ove th ree special 3. Cut new piece of g lass channel ru b b er fille r, CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 68 Use eith er a push o r pull type spring scale, p o si­ tioned at r e a r edge of vent g la ss. Turning adjust­ m ent nut clockw ise in c re a se s operating tension. Figure 23—Vent Window Attachment CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 69 Window g lass rub b er fille r is supplied in 3. Install two screw s attaching low er channel th re e thick nesses - 0.037", 0.047", and 0.057" - CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 70 "Door Vent Window Assem bly R eplacem ent." 6. Check operation of vent assem bly and win­ dow ra isin g and lowering action fo r possible binding. Figure 28—Installing Window Glass Channel Run CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL-...
  • Page 71 11. D isconnect speedom eter cable at tra n s ­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 72 The fan speed control r e s is to r unit is CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 73 CAB AND BODY MOUNTINGS 1-42 “ AIR” T-2428 HEATER CONTROLS figure 30— Air Flow Heater CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 74 1. H eater hoses a r e kinked, d e terio rated , o r sw itched around at the co re piping. 2. H eater core plugged. 3. P oor blow er m otor ground connection. 4. Blower m alfunctioning. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 75 "AIR CONDITIONING" sub -sectio n at end of th is section. NOTE R efer to "GENERAL MAINTENANCE" at beginning of th is section for inform ation on straightening, refinishing, and painting of. cab which will apply. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 76 Outside handles a r e stationary-type screw retained to door Figure 1 —Tilt Cab Interior Construction and have a push button-type latch control. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 77 C A B R E A R M O U N T I N G C A B F R O N T M O U N T I N G Figure 3—Cab Mountings CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 78 4. R ev erse the above procedu re to in stall o r lengthening catch re le a se rod. A fter adjusting tra c k assem bly. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 79 A ccess to one cap screw at door upper prop erly located in door opening, will have equal hinge is gained afte r rem ov ing plugfrom door inner clearan ce around its p e rim e te r. panel. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 80 M ark position of s trik e r bolt sp a c e r o r bolt and in stall o r rem ove shim sp a c e rs. Spacers w asher on door p illa r using pencil o r crayon. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 81 DOOR OUTSIDE HANDLE REPLACEMENT REMOVAL Remove eight screw s which attach ac c e ss panel to low er portion of door. Remove ac cess panel. Figure 11 —Door Handle Installation CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 82 Figure 15—Disengaging Door Inside Handle 2. While holding cylinder, in s e rt legs of r e - CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 83 To in sta ll eith er handle, fo rce handle and escutcheon p late. w ith in stalled lock sprin g over spindle until lock NOTE: The low er view in figure 15 shows how spring becom es fully engaged. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 84 Install lock m echanism with rod s and rem ote control in re v e rs e of the "Removal" p ro ced u res. Figure 19—Lowering Regulator from Door IMPORTANT: Make s u re to u se the th ree CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 85 5. C arefully position edge of g la ss regu lato r channel 1.24-inch from low er right co rn e r (fig. 21) and then p r e s s channel ov er g lass and glazing CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 86 3. In stall channel(s) in re v e rs e o rd e r of r e ­ spring sca le positioned at r e a r edge of g lass. moval p ro ced u res. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 87 2. P ull w eath erstrip from door, then scrap e INSTALLATION any rubber o r adhesive m ateria l which may have 1. Thoroughly clean inside of glass,channels becom e bonded to door su rface. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 88 NOTE: A wood 4 x 4, 1 feet long positioned CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL •...
  • Page 89 NOTE: Left support can be rem oved from cab, if d esired . CAB INSTALLATION In stall lifting sling and chainfall to cab Figure 30—Mounting of Cob Rear Support with doors slightly open (fig. 29). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 90 8. Tighten steerin g coupling clam p bolt to 40- tach to rsio n b a r anchor le v e r to cab mounting left 50 foot-pounds torque. Connect speedom eter cable CHEVROLET" SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 91 IMPORTANT: F inal check tightness of anchor to rsio n b a r tension adjustm ent a s d irected la te r. lev er bolt nut. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 92 C arpeting is lam inated to 1/2" re sin im pregnated tufflex with a polyethylene pigmented skin. F loor Figure 1 —Aluminum Til I Cab (90) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 93 ­ sion g earshift lever(s) in N eutral, and apply p a rk - Figure 2—Cob Tilting Hydraulic Pump (Typical) Figure 4—Cab Rear Mounting and Catch (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 94 20 Relief Valve 6 Clevis Pin - Beam 21 Suction Screen 14 Snap Ring 7 Pin T-6261 15 Valve Spool 8 Clip - Piston Head Figure S —Schematic of Hydraulic Pump Assembly (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL"...
  • Page 95 Since the system is of the closed re s e rv o ir PUMP REPLACEMENT (Fig. 6) type, a ir space above oil is necessary to prevent 1. Remove hydraulic hoses from control CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 96 . should operate norm ally. The o il then p a ss e s through a hollow s e t screw CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 97 This suction is sufficient to O -rin g s. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 98 Also latching a rm re tu rn spring and pin can be r e ­ viously rem oved. Connect hydraulic line and bleed moved if n ecessary (fig. 10). a s describ ed la te r. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 99 5. In stall on vehicle a s described under cab a ir - f r e e oil flows from loose connection at tilt lock assem bly replacem ent. cylinder. Tighten connection firm ly. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 100 3. E xhaust a ir supply from a ir tanks by preceding "CAB Tilting In stru c tio n s." opening tank d ra in cocks. Figure 13—Cab Lifting Sling Attachment CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 101 25-30 foot­ 17. Lower cab a fte r placing wooden blocks pounds torque. in the “ V” of both r e a r mountings to p revent CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 102 4. Install and adjust s trik e r bolt a s d irected in next pro ced u re. SPACER PLASTIC WASHER TAPPED FLOATING! STRIKER BOLT PLATE AND WASHER T -5 765 Figure 75—Door Striker Bolt and Washers CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 103 ­ p re s sio n in the g re a se o r paint. Figure 18—Door Release Components 3. M easure distance between head of bolt and CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 104 D oor R ear Edge "In" o r "Out" of A djustm ent To align door r e a r su rface flush with cab, Figure 21 —Remote Control and Lock Mechanism p ro c eed as follows: CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 105 Figure 22—Door Components clea ran c e between re le a s e button plunger and ( w /M anual Window ControfJ lock m echanism le v e r. If insufficient clearance CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 106 “ R em oval" p ro ­ Figure 23—Door Components ced u res. Tighten screw s firm ly then check op­ Iw/Electric Window Control) eratio n of com ponents. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 107 8. T ilt reg u lato r assem bly to rem ove arm fram e and at end of fra m e . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 108 (Refer to figure 22). 4. Remove th ree screw s which re ta in vent Figure 27—Installing Glass Run Channel window to upper front edge of door. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 109 Use thum bs to p re s s channel into position. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 110 IMPORTANT Always w ear heavy gloves to prevent possib le injury when handling g lass. F o r inform ation on servicing se a ts, re fe r to next page. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 111 . Tighten se a t-to -p la tfo rm nuts to 5-8 foot-pounds torque and p la tfo rm -to -flo c r bolts to 15-20 foot-pounds torque. Figure Seat Adjustment 3 0 —Standard Figure 32—Air Suspended Seat (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 112 ­ com partm ent h ea te r. b o ssed black vinyl. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 113 (SEC. 1A) at beginning of this group for applicable inform ation on straightening, dinging, refinishing and painting of cab components. IMPORTANT Always w ear heavy type gloves to prevent possible injury when handling glass. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 114 Be carefu l not to bend moulding o r dam age cab paint. 3. To in stall, carefully snap o uter moulding and clip re ta in e rs in place. P osition inner mould­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 115 COACH-TYPE MIRROR (Fig. 39) A coach-type m irro r is bracket-m ounted to Figure 37—Cab Step Assist Installation each fro n t co rn er panel. M irro r and a rm assem bly CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 116 R eplace door. ru b b e r moulding around head. LOCK ROD SUPPORT BRKT. SPRING LATCH ROD COVER DOO R ASSY. VIEW A T-aiPi Figure 40—Luggage Compartment Door Installation CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 117 Cut ing bolts a re tightened sec u r ely . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 118 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 119 MAIN HEATER OUTSIDE AIR INLET TO DEFROSTER TO HEATER OUTLETS OUTLETS (ABOVE DASH) (BELOW DASH) AIR FLOW HEATED AIR FLOW CONTROL CABLES ELECTRICAL WIRING T-6959 Figure 42—Healer Air Flow and Control Schematic CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 120 M odels with a sle e p e r cab have an auxiliary heating sy ste m . There a r e two controls for oper­ Figure 45—Console Access Panels ating this sy ste m . The control knobs are located CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 121 4 . D isconnect coolant lin e s from main heater cables (refer to fig. 42). co re and sle e p e r heater core (when u sed ). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 122 . 5. R em ove sc r e w s attaching main heater hous­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 123 7. Connect battery ground cable. so le A c c e s s P anel andH eater C over R eplacem ent." W ARNING N ever sleep in cab u n less adequate ventilation is provided. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 124 8 Lock Nut 1 Frame Side Rail 5 Clip Plate 9 Nut 2 Longitudinal Sill 3 Spacer Block 6 Metal Channel 10 Cross Sill 7 Mounting Bolt TP-9174 Figure 1—Typical Body Mountings CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 125 (studs) can a lso be su cc essfu lly mounting of s ill channels. em ployed. If design of body does not perm it use CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 126 "Mounting B olts." The num­ with p la tes or w a sh ers. ber of clip s to u se is of cou rse dependent upon CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 127 CAB AND BODY MOUNTINGS 1-96 IMPORTANT DO NOT d rill additional holes in frame. DO NOT weld heat-treated frame. Refer to FRAM E (SEC. 2) for additional cautions. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 128 The receiver-d eh yd rator, bracket mounted to taining a predeterm ined minimum refrigerant right sid e of radiator sh e ll or sheet m etal, is de­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 129 Chart" at the end of th is section for trouble­ the sleep er heater core into ducts that lead to rear shooting the sy ste m s. corner outlets in sle e p e r com partm ent. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 130 LOW PRESSURE SERVICE GAUGE VALVE COMPRESSOR EQUALIZER LINE EVAPORATOR RECEIVER-DEHYDRATOR EXPANSION VALVE HIGH PRESSURE SERVICE GAUGE VALVE HIGH PRESSURE HOSE HIGH PRESSURE LOW PRESSURE T-6947 REFRIGERANT REFRIGERANT Figure 3—Schematic of Refrigerant Circulation (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 131 TO DEFROSTER (FRONT OF TO HEATER OUTLETS DRIVER) OUTLETS (ABOVE DASH) (BELOW DASH) HEATED AIR FLOW CONTROL CABLES •m • i ELECTRICAL WIRING T-6205 Figure 4—Air Flow and Control Schematic IAluminum Tilt Cab Model) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 132 . To obtain g rea ter a irflo w , use "FAN" sw itch. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 133 "High Speed." A ir flow w ill be directed "DEFROST" knob controls flow of a ir to the through heater ou tlets and not A /C ou tlets. windshield d efroster ducts. With knob a ll the way CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 134 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 135 75 pounds changing it to steam rather than raisin g the tem p­ p er -sq u a re -in c h . erature. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 136 W eighing drums before and during the tran sfer 5. In the evaporator, w here the p re ssu r e is w ill determ ine fu lln e ss of drum s. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 137 When the a ir conditioning sy ste m fir s t begins is an in c r e a se in tem perature of the gaseous r e ­ to operate, the co m p resso r w ill im m ediately begin CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 138 CAB AND BODY MOUNTINGS 1-107 Figure 8—Air Conditioning and Heater Control (Aluminum Tilt Cab Model) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 139 CAB AND BODY MOUNTINGS 1-108 HEATER SWITCH ASSEMBLY AIR TEMPERATURE CONTROL SUCTION THROTTLING VALVE AIR TEMPERATURE CONTROL CABLE SUCTION THROTTLING CONTROL CABLE AIR CONTROL CABLE T-6885 Figure 9—Air Conditioning and Heater Control (Conventional Cab Model) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 140 B LO W E R , AIR INLET ASSEM BLY REAR DUCT FRONT DUCT C EN TER DUCT AIR INTAKE DUCTS T-6944 Figure I 0—Heater and Air Intake (Aluminum Tilt Cab Model) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 141 AND CORE ASSEMBLY CON N ECTIN G TUBES DOOR CONTROL BRACKET M OTOR AN D M O U N T IN G PLATE CORE RETAINER T-6886 Figure 11 —Heater Evaporator Blower (Conventional Cab Model) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 142 CAB AND BODY MOUNTINGS 1-111 THERMO EX P A N S IO N V A LV E DRIVER'S A / C AN D DEFROSTER DISTRIBUTOR T.4945 Figure 72—Air Conditioning and Defroster (Aluminum Tiff Cab ModelI CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 143 CAB AND BODY MOUNTINGS 1-112 Figure 13—Air Conditioning Air Outlets and Hoses IConventional Cab Model) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 144 ­ su rfa ce of the evaporator co re and is drained off placed sin ce it is neither repairable or adjustable. a s w ater. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 145 The pulley assem b ly contains an e lectrica lly Figure J 6—Suction Throttling Valve controlled m agnetic clutch, perm itting the com ­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 146 When the "AIR COND. "knob is placed in "OFF," refrigeran t. the e le c tr ic a l circu it to the co m p resso r clutch is CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 147 Should liquid refrigeran t com e in contact with the skin, the injured a rea should be treated the sam e a s frostbitten skin. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 148 They are to rem ain sea led until 4 . Check for refrigeran t leaks and ob serv e just p rior to making connections. refrigeran t pa ssin g through the sight g la ss with CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 149: Refrigerant Lines

    R eg a rd less of whether or not the s y s ­ would indicate that the e le c tr ic a l c irc u its are func­ tem is charged, it m ust rem ain sea led to prevent tioning properly. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 150 . Continue checking overch arge i s indicated. V erify with a p e r­ out sy ste m using perform ance checks out­ form ance check. lined in this manual. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 151 , m ove "AIR COND" le v e r to "OFF." for other pertinent air conditioning inform ation T his should disengage the com p resso r clutch. If related to perform ance testin g. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 152 R efrigerant te st fitting gauge p r e ssu r e . . L ocate a calibrated therm om eter in center e. C enter outlet tem perature. outlet. Sensing bulb must not touch m etal. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 153 NOTE: F or altitude le v e ls at or near sea le v el, R eferen ce should be made in the order liste d with se t the suction throttling valve a s sp ecified (23 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 154: Depressurizing The System

    (J-9459) Schrader valve adapter at the discharge gauge fitting. sy ste m , thereby creating a vacuum in the sy stem . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 155 3. Check oil le v e l in vacuum pump (J-5428-02) been co rrected , evacuate the sy stem again for 15 and add F rig id a ire-1 5 0 v isc o sity o il or equivalent, m inutes. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...

  • Page 156: Charging The System

    SIDE," and then p la ce "TEMP" lev er to fu ll cold of refrigeran t in receiver-d eh yd rator. If bubbles p ositio n . Open low p r e s s u r e valve on gauge se t CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 157 ­ or injury to personnel. tainer until tight. DO NOT open outlet valve during this operation as turning the valve into the retainer CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 158: Adding Refrigerant (Small Amount)

    . See "Adding O il” 5. With sy ste m purged a s d irected p reviou sly, run pump until 26-28 inches of vacuum is obtained. la ter . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 159: Checking Compressor Oil Level And Adding Oil

    Note total amount of re fr ig e r ­ if low com p resso r oil le v e l i s suspected, a quick ant added. check may be perform ed as follow s: CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 160: Checking For Leaks

    3. Thread detector unit onto top of fu el cylin ­ d er. Tighten finger-tigh t. ner (se e fig. 24): CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...

  • Page 161: Replacing Compressor

    Consequently, do not rep lace com p ressor w ill be indicated by a change in color to b rillian t se a l until the sy stem is properly check edfor lea k s. CHEVROLET SERIES 70 90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 162 , rep lace the CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 163 3. R em ove cover plate over co m p resso r open­ in gs very slow ly to bleed off p r essu re. Figure 28—Compressor Mounting (6-71 Conv. Cab Model) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 164: Servicing Leaking Seals And Hoses

    DO NOT add any m ore o il than is n e ce ssa r y or m aximum co o l­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 165: Condenser Assembly Replacement

    "Cab and Sleeper Com­ NOTE: B e su re to wrap insulating tape around partment" in "ALUMINUM TILT CABS" (SEC. ID). in sta lled capillary bulb and evaporator outlet pipe. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...

  • Page 166: Expansion V Alve R Eplacem Ent (Conventional C A B )

    (mounted on evaporator core out­ S ee "Checking C om p ressor O il L evel and Adding le t tube), is covered with insulation tape. Oil" explained p reviou sly. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 167: Suction Throttling Valve Replacement

    (when used) from in sid e cab. INSTALLATION 13. If d esired , a ir distributor and sleep er 1. R eplace the suction throttling valve by con­ heater can be rem oved from main heater housing. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 168: Collision Service

    A lso , disconnect blow er motor ground w ire m ust be detached from the evaporator outlet tube. at dash. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 169 INUM TILT CABS" (SEC. ID) of this manual for sea t replacem ent p rocedures. 3. D isconnect ele ctrica l lead s from blower Figure 34—Blower Motor Wiring Connection m otors. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 170 To ensure maximum m oistu re protection, do not connect the r e c e iv e r - dehydrator until a ll other a sse m b lie s have been connected. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 171 Replace belt slippage and listen expansion valve. See Note "E ." fo r unusual n o ises. -6878 *S.T. - Suctioning Throttling. Figure 35—Diagnosis Chart for Air Conditioning CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 172 If suction p r e ss u r e s a lso rem ain ed, discard the valve rem oved. high, then the P.O .A . or suction throttling NOTE: Specifications are found on the following page. T-6879 Figure 36—Diagnosis Chart Notes CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 173: R Efrigerant Line Connection Torque S P E C I F I C A T I O N

    Although the torch flam e is sm a ll and w e ll p ro­ tected , it is recom m ended that a fir e extinguisher be placed n ear-by for any em ergency that may a r ise . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 174 " of the cen terlin e, the portion of the fram e se le c ted on the le ft sid e rail, a corresponding point Figure 1 —Typical Frame Alignment Points CHEVROLET SERIES 70-90 HEAVY. DUTY TRUCK SHOP MANUAL...
  • Page 175 S.A .E . 1023 b ase r a ils. M a x . B en d in g M o m ent T-2993 Figure 2—Frame Bending Moment (Typical Tractor) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK5HOP MANUAL...
  • Page 176 However, it must w here n ecessa ry . Figure 3 —Frame Bending Moment (Typical Straight Truck) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 177 Instructions.") of U -bolts for attachment of fifth w heels or bodies T-2994 Figure 4 —Frame Bending Moment (Typical Dump Truck) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 178 E12016 or E11018. Following a re the d escrip tion s of the types of w elds; hole in the web section . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 179 F or th is reason it is extrem ely important that all reinforcem ent Figure 6 —Scarfed (Tapered) Ends of Reinforcement ends be scarfed to change section modulus as grad­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 180 The inverted "J" reinforcem ent is attached to the 2. R einforcem en ts, with the exception of strap web section only with a spaced bolt pattern. This CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 181 $ide r a ils. ends overlap by eight to ten inches. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 182 S id e Rail M aterial Identification (Lo catio n — C en terlin e of Front A xle) H E A T -T R E A T E D SA E1023 SA E9 5 0 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 183 FRAME 2-10 Fram e rep airs should be undertaken only by com petent m echanics, and only the recom m ended m aterials should be used. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 184 2. F ailure to rotate tir e s . 3. R efer to Load and Inflation Table (SEC. 10). 3. Improper tir e inflation. 4. Overloaded or im properly loaded. 4. Avoid overloading v eh icle. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP M ANUAl...
  • Page 185 5. Check kingpins for lo o se n e ss. to sc r ib e the tir e s , otherw ise the front w heels w ill CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 186 , straighten or replace w heel. term ined and added to the c a ste r angle to obtain a 3. P la ce v eh icle on le v e l su rfa ce, with norm al CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 187 "corrected caster" for left w heel. axle is bent or tw isted , refer to "FRONT AXLE" (SEC. 3B) for c o rrectiv e inform ation. To determ ine "corrected caster" with various CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 188 ° + 3 0 ' (Sp e cial Equipm ent) ♦Regardless of maximum turning angles specified, adjustment of stop screws must provide 5 /g-inch minimum clearance of tire with any chassis components. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 189 . If draw key h oles becom e enlarged beyond Figure 1 —Steering Knuckle Construction (Corp. F070 Axle) u se of new key, replace axle cen ter. IT IS NOT CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 190 IMPORTANT: When in stallin g o v e r siz e tir e s , F E -970 a x le s. On F -160 a x le s, stop sc re w s are in­ recheck turning clearance and stop scr ew setting. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 191 L ubrica­ 3A. P r e c isio n equipment is n ecessa ry to check axle tion fittings are provided at upper and low er ends on v eh icle. of knuckle. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 192 (SEC. 0) of this m anual. Try action of steerin g bottom. Bushings a re sp lit D elrin and are of float­ knuckle for binding condition. ing type. 10. In stall steerin g arm s to knuckles. Install CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 193 Install brake m echanism and hubs. Check 4. R em ove cotter pin, king pin nut, and ste e l front end alignm ent fa ctors and stop sc re w settin g. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 194 L arge end of key m ust be r e c e sse d into axle cen ter hole no le s s than 1 /8 inch or m ore than 3 /8 inch. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 195 K e y t o n e o r c h l o r in a t e d s o l ­ able, u se M agna-Flux method to check axle center v e n t . for minute fractu res. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 196 Advance to Next Advance to Next Cotter Pin Hole Cotter Pin Hole King Pin Bearing Cap, Cap S c r e w . *D elrin B ushing— No Finishing Required **R eam after Installation CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 197 At regular in terv a ls, spring U -b olts should be ation. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 198 FRONT SUSPENSION 3-15 Figure 1 —Front and Rear Mountings (Front Spring) (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 199 (5) and spring eye a s shown in figure 3. DO bushing rem over and in sta lle r tool se t (J-21058) NOT HAMMER ON LINK STUDS. a s shown in fig u res 9 and 10. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 200 Mark down one sid e of springs to a ssu re g re a se to each leaf. Align center bolt holes in original position of le a v e s, then p lace spring a s ­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 201 3 Eye Leaf B Delrir L iner 9 R ear Eye Bushing NON-SYMETRICAL (Dimensions A and B be ing unei ^ual) T-6775 Figure 5—Tapered Leaf Front Spring Assembly tNon Symetrical Type Spring) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 202 . Install the shock absorber bracket, U -bolt Figure 7—Removing Spring Pin or Bolt with sp a cer, U -b olts, and nuts. Slide Hammer and Adapter CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 203 IMPORTANT: U -b olts must be retightened to torque listed in "Specifications" after 500 m ile s Figure 9—Removing Rubber Type Eye Bushing when new, or after spring repair or replacem ent. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 204 ........0.043" CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 205 FRONT SUSPENSION 3-22 GOOD FRONT SPRING AND SHOCK ABSORBER MAINTENANCE PAYS DIVIDENDS IN DRIVER SATISFACTION AND LESS CHASSIS REPAIR. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 206 New hub o il s e a ls should be in stalled when u re using a new gasket ( th ere is the slig h te st indication of leakage, w ear, CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 207 7 Clamp 14 Inner Bearing Cup 22 Hub Cap T-6696 Wheel Nut 15 Inner Bearing Cone and R o llers Figure J — Front Hubs and Bearings (with Cast Type Wheels) (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 208 20 Wheel Stud 13 Outer B earing Cup Wheel Nut T-6695 14 Outer B earing Cone and R o llers 7 Wheel Figure 2—Front Hobs and Bearings (with Disc Type WheelsI (TypicalI CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 209 3. P la c e inner bearing cone and r o lle r a s s e m ­ bly in hub. 4. Back off the adjusting nut 1 /4 to 1 /3 turn. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 210 10. Readjust front w heel drive speedom eter gear backlash a s outlined under "Front A xle Speed­ om eter D rive" in "FRONT AXLE" (SEC. 3B) of Figure 5—Oil Level (Oil Lubricated Type Bearings) th is manual. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 211 B earing Cup R eplacem ent Figure 7—Front Wheel Bearing Adjustment Bearing cups are rem oved by using a m ild Components IFE900 Axle) s te e l rod through opposite end of hub and driving CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 212 W heel B olt R eplacem ent are firm ly bottomed in tapped h oles and that IMPORTANT: If any wheel ex p erien ces a threads are not damaged during installation. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 213 FRONT SUSPENSION 3-30 R eplacem ent of parts which show appreciable wear is m ore econom ical than a prem ature o v er­ haul resulting from continued u se of worn p arts. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 214 Thus an in­ HIGH and to opposite field when in LOW. creased load is put on the spring, and in this CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 215 Lock is shifted by a power Figure 2—Two-Speed Electric Shift Unit Installed shift sy stem , controlled by a control le v e r on IEaton Axle Shown) instrum ent panel in cab (fig. 4). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 216 When Figure 5 —Three-Speed Control Switch (Air) torque on axle g ea rs is reliev ed by relea sin g the CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 217 Check tigh tn ess of stud nuts at regular MOUNTING in tervals. Tighten 1/2" nuts to 50-60 ft.-lb s. Check for axle m isalignm ent. Select a point torque, or 5/8" nuts to 90-110 ft.-lb s . torque. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 218 A The preceding te s ts should readily lo ca liz e CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 219 (100 to 105 lb s.). P lace under individual headings. REFER TO NEXT PAGE FOR REAR AXLE SERVICE DIAGNOSIS CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 220 Some types of a x le s require additional lubricant at pinion cage when filled cham bers. R efer to resp ectiv e su b -sectio n s for in stru ction s. in itially or after overhaul. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 221 Inspect axle housing for lubricant leak s be­ fo re cleaning, then steam clean thoroughly to r e ­ Figure 9—Propeller Shaft Yoke Holding Bar m ove a ll dirt or other foreign m atter. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 222 On a x le s using cap scr ew s, 2. Rem ove stud nuts, cap screw , and lock CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 223 . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 224 3. L oosen shift u n it-to-d ifferen tial c a rrier stud nuts (fig. 13) to rem ove preload from shift unit spring. Figure IS —Shift Unit Seal Markings CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 225 U se suitable tool to p r e s s or drive retainer Figure 17—Inter-Axle Air Shift Chamber and Spring (Eaton) into ca rrier until seated against flat w asher. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 226 3. U sing p lie r s , rem ove two snap rings from Figure 20—Inter-Axle Vacuum Shift Chamber (Eaton) shift cham ber shaft (fig. 18). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 227 25 Shift Housing Cover Gasket 26 Shift Housing Cover and Detent Spring 27 Lubricant Plug 28 Housing Cover to Housing Screw (with Washer) TP-8598 -1 Figure 21 —Electric Shift Unit Components (Batoni CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 228 ) nut w ill be at either top or bottom depending (16) which attach bearing cover (15). Remove Figure 23—Removing Shaft, Actuating Lever, and Spring Figure 22—Position of Drive Nut When Disassembling CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 229 (24) u n less n ecessa ry to replace 2. Push down on drive screw assem b ly (20) T P-6607 Figure 25—Removing Motor W/tes Figure 27—Removing Automatic Switch CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 230 P lace Tighten sc r e w s and nuts firm ly. m otor in v is e , and grasp wrench handle with one CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 231 26 L u b ric a n t Plug 27 H ousing C over to Housing Screw (with W asher) 28 Housing to C a r r ie r Seal Figure 29—Shift Unit Components IRockwellI CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 232 Retain bearing with bearing lock nut (13). Figure 32—Assembling Torsion Spring and Levers (Eaton) 5. Run nut to center of screw , then in sert CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 233 . n u t s i n . l b s . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 234 A c t u a t i n g L e v e r P i n O - r i n g T - 4 6 0 5 Figure 34—Three-Speed Air Shift Unit Components CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 235 Figure 37—Removing or Installing Piston, Figure 36—Clevis Pin Removal or Installation Push Rod, and Spring CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 236 T -3 3 2 8 C h a m b e r H a l f ( O u t e r ) Figure 40—Inter-Axle Differential Lock Control Valve Figure 39—Inter-Axle Vacuum Shift Chamber CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 237 A X L E S H A F T F L A N G E S TUD N UT V i" ............................50-60 5 / s " ............................9 0 -1 10 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 238 , b o l t s , s p a c e r s , a n d n u t s . r a d i u s l e a f p i n . A t t a c h s l i d e h a m m e r CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 239 Not Used With 5* Pinion Angle TORQUE ROD U-BOLT SPACER' -BOLT ASSEMBLY REAR AXLE U-BOLT NUT ASSEMBLY SPRING ANCHOR PLATE CONVENTIONAL CAB MODELS (TYPICAL) T-6822 Figure I —Link Type Rear Suspension (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 240 Check U-bolt nuts fo r p ro p er to rq u e. R efer to "Specifications" at end of this Figure 4 —Removing Radius Leaf Pin with sectio n fo r torque. Slide Hammer and Adapter CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 241 An a ir gap between helper spring and STA R T IN G R E M O V A L W ITH SO C K ET H A N D LE Figure 6—Removing Spring Eye Bushing CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 242 26 Saddle Caps 12 Lock Nut 13 Lock W asher 14 Top Pad Slide _______________________ CO M PO N EN TS DISASSEM BLED ______________________ Figure 8 —Tandem Rear Axle Suspension (Hendrickson RTI (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 243 When a m ajor overhaul is req u ired , the com ­ 6. P lace jacks and other equipment at each p lete tandem unit should be rem oved from the CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 244 5 F ram e Bracket (Front) 20 Spacer 13 Spring Saddle Cap 6 F ram e 14 Equalizing Beam T-6820 7 F orw ard R ear Axle Figure 9—Tandem Rear Axle Suspension (Hendrickson RU) (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 245 -40-50 FT.-LBS. NUT TORQUE TORQUE ROD 200-250 FT.-LBS 90-110 FT.-LBS. 190-210 FT.-LBS. 225-275 FT.LBS. SADDLE CAP CROSS TUBE FRONT EQUALIZING BEAM t-6819 Figure 10—Tandem Rear Axle Suspension (Hendrickson RS-380) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 246 "R ep air." 4. Inspect spring fo r loose o r broken rebound leaves in vise o r a rb o r p re s s . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 247 Install lubrication fitting. fre e height of le s s than 3-11/16 inches should be 5. Install rebound bolt in low er end of r e a r replaced. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 248 P osition beam s, with c ro ss tube in place Figure 14—Section Through Spring Saddle and Beam (RT Type Suspension) at sp ring saddles (fig. 8 o r 9) and axle b ra ck ets. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 249 Check tap ered hole in fram e and axle b ra ck ets for Figure 16—Adapter and Retaining Bolt at Axle Bracket w ear by checking fit of new torque ro d end stud in CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 250 TANDEM UNIT INSTALLATION Roll axles and w heels, with ro c k er a rm s c ro s s tube, and sprin g s attached, in position under fram e. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 251 13 C om pression Cap 4 Pedestal Spacer 9 U-bolt 14 R ocker A rm 5 F ram e 10 Insulator Cap 15 Spring Cap -6821 Figure J 8—Page and Page (LWH) Rear Suspension Installed (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 252 Spring A ssem bly Spring Cam Trunnion Mount Axle Bracket Adapter Bolt P edestal to C ro ss Tube Nut C ro ss Tube Figure 19—Page and Page ILWH) Rear Suspension Removed (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 253 10 F ra m e R ear Spring R ear 17 C om pression Bolt Lock Bolt Spring (R ear Unit) Hanger Spacer 18 C om pression W asher__________ T-l 01 8 Figure 20—Page and Page 800 Tandem Suspension CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 254 "Page and P age 800 Suspension System ." at inside of fram e. 5. Remove blocks and jacks from under fram e. 6. Remove sp rin g assem bly from vehicle. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 255 7. Remove ro c k er a rm by pulling straig h t off Inspect ru b ber bushings for d eterio ratio n . hanger pivot pin. R eplace if n ec essary . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 256 The vehicle load is equalized through the leveling broken rad iu s leaf. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 257 1. Stack sp rin g leaves in c o rre c t o rd e r using CENTER SPRING HANGER Figure 21 —Reyco 101 Suspension CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 258 If axle is suspected to be out of alignm ent, the eye is lined up with opening in spring hanger following procedure m ust be followed to inspect, b rack et. Figure 22—Reyco Tandem Alignment Chart CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 259 , additional adjustm ent can be made from zontal cen ter of wheel, and m ark wheel rim lip at o th er sid e of axle. th is point. R epeat operation fo r opposite side of CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 260 F o r Specifications concerning Leaf Type Suspensions, re fe r to the end of Section 4B. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 261 . The at each r e a r axle to dampen suspension o sc ill­ valve does not respond to rapid re la tiv e motion Figure 1 —Suspension Air System CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 262 At r e a r axles, place a block fro m hanging by bellows only. between axle housings and fram e to prevent sudden Figure 3 —Air Suspension Components CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 263 P osition D elrin lin e rs , one on top and one valve. at bottom of control arm . These can be held in CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 264 Check mounting studs on bead p lates fo r damaged o r stripped th rea d s. Figure 5—Pressure Regulating Valve T h reads in fitting holes should be in good condition. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 265 . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 266 Exhaust V a lv e Exhaust V a lv e Exhaust V a lv e Lever Lever Lever NEUTRAL U N LO A D IN G LO A D IN G Figure 6—Operation of Height Control Valve CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 267 23 Inlet Adapter and Check 35 Delay Cover 11 O vertravel Control Shaft Valve Assembly 36 Delay Cover R etainer 12 Shaft O -ring (Large) 24 Outlet Adapter T-1446 Figure 7—Height Control Valve Components CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 268 D irt and sealing compound m ust be kept out of CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 269 NOTE: The following tools shouldbe used when position, re s e t indicator dial to zero (0), which p erform ing valve adjustm ents: actually is 0.100” on indicator of type reg isterin g CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 270 0.035" to 0.037" from center position. If n e c e ssa ry , bend exhaust valve lev er to c o rre c t Figure 11 —Adjusting Air Valve Lever Gap setting (fig. 11). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 271 1. Connect a ir p re s s u r e supply hose to valve a ir inlet p o rt (fig. 8). Figure 13—Silicone Fluid Level 2. Move the o v ertrav el le v e r upward (quickly) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 272 M akeshift tools may b reak off chips that could locjge between valve and sea ts. C hips, d irt, and o ther foreign m ateria l could cause Figure 15—Replacing Valve Core Assemblies faulty valve operation. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 273 (fig. 16). C om press springs only screw . R efer to figure 16. enough to allow shaft to be in serted . Install o v er­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 274 . .1 . 2 4 7 " 1.2 48 " Sp rin g Ey e Pin ( O . D . ) ................m e ' L G T ....................... *Ream at assembly. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 275 Lo w er M o u n tin g B o l t ..............70-80 N u t Shock Absorbe r U p pe r Bra cke t to Fra m e Bolt. N u t 90 -110 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 276 . If m ovement is excessive, 9. Install axle shaft as directed in "REAR adjust as d irected under "Wheel Bearing A djust­ m ent" following: AXLES" (SEC. 4A). Figure I —Rear Wheel Bearing Adjustment Nuts CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 277 2. If brake drum is dem ountable type, rem ove vent o uter bearing cone and ro lle r assem bly from b rake drum . dropping on flo o r. Remove outer bearing assem bly. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 278 6. Install brake drum (if rem oved). Install Coat oil seal bore in Aub with a thin lay er of non­ tir e and rim assem bly or tire and wheel assem bly. hardening sealing compound. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 279 Cups w iper se a ts squarely and that sealing su rface on m ust seat firm ly against shoulder in hub. sleeve is not dam aged in any way. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 280 If a single p ro p e lle r shaft is used, slip joint is at on following page when servicing p ro p e lle r shafts. Figure J —Typical Propeller Shaft Combinations CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 281 8 P ro peller Shaft Yoke 3 Special Cap Screw 6 Tie Bar 9 Lock W asher -8245 Figure 2 —Type 58WB an d 68 WB Universal Joint Showing High and Low Wing Bearings CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 282 View B illu s ­ un iv ersa l joints as described la te r in this section. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 283 5. Remove the o th er two b earin g s in the sam e Remove special cap screw s and lock w ashers m anner to p e rm it rem oving journal. attaching bearing cages on opposite ends of jo u r­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 284 13 Oil P assag e G asket R etainer 14 Axle D rive Pinion 7 Aligning A rrow s Yoke W asher (Cork) Figure 5 —Typical Propeller Shaft with Type 1700 or 1800 Universal Joints CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 285 BEARING IN CLEANING FLUID. G rease re ta in e rs and slin g e rs a re serv iced only as a p a rt of the bearing assem bly. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 286 NOTE: wing bearings (fig. 2) have BRICATION (SEC. 0) and torque attaching p a rts to threaded holes in bearing cage flanges and are "Specifications" liste d at end of this section. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 287 REAR SUSPENSION 4-74 TPM-9995 Figure 7—Checking Drive Line Angles CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 288 M easurem ents at both ends of each m ade, if n e c e ssa ry , by using shim s at upper c ro ss beam m ust be equal. Make adjustm ents as CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 289 25-30 60-70 85-105 15-20 25-30 1700 35-45 25-30 33-38 33-38 15-20 40-50 1800 35-45 25-30 33-38 33-38 15-20 40-50 58 W B - 6 8 W B 40-50 60-70 40-50 15-20 25-30 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 290 1.3 2 0 1"-1.3 2 0 6 " 3 /s-24 U - B O L T 20-24 0.920"-0.925" 1800 1.70 0 "-1.6 9 6 " 0 .12 4 7"-0 .12 5 0 " CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 291 . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 292 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 293 R e f i l l s y s t e m w i t h r e c ­ a n d o m m e n d e d f l u i d . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 294 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 295 Do not use a replacement part of lesser quality or sub­ stitute design. Torque values must be used as specified during reassembly to assure proper retention of this part. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 296 P e d a l S u p p o r t S i l l P i n a n d B u s h i n g A s s y . T-2552 Figure 7—Brake Pedal and Master Cylinder Installation (Tilt Cab Models) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 297 . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 298 , i n s p e c t i o n a n d r e p a i r , a n d a s s e m b l y CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 299 . M a k e CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 300 R e t a i n e r R i n g R e s e r v o i r H o u s i n g Figure 9—Split System Master Cylinder CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 301 - r e a r w h e e l . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 302 Figure —W heel Cylinders e a c h c y l i n d e r . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 303 . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 304 " C O N N E C T I N G B R A C K E T T U B E Figure 13—Power Cylinder Installed (Tilt Cab Models) Figure 12—Power Cylinder Installed (Conv. Cab Models) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL'...
  • Page 305 - Figure 14—Power Cylinder Air Cleaner Installed (Tilt Cab) Figure 15—Power Cylinder A ir Cleaner Installed (Conv. Cab) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 306 ( s e e f i g . 1 6 ) . Figure 16—Vacuum Check Valves Installed CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 307 , b o t h s h o e s a r e r e v e r s e a c t i n g s i n c e CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 308 . T h e s u p p o r t s CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 309 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 310 , c r a c k e d , w e a k e n e d . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 311 1 2 . A s s e m b l e l o n g l i n k ” S ” h o o k t o l o n g a r m CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 312 , S A F E T Y P R E C A U T I O N . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 313 R e p l a c e r e s u r f a c e d r u m s R . H . a n d L . H . p a i r s . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 314 . T h i n d r u m . A d j u s t . D r a g g i n g b r a k e s . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 315 . L u b r i c a t e t h e s h o e l e d g e s . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 316 L o o s e b a c k i n g p l a t e , d r u m , w h e e l c y l i n d e r . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 317 . S t u c k c h e c k v a l v e . R e p l a c e v a l v e . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 318 . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 319 Slave Cylin der B o r e ......1 .1 9 " 1 .1 9 " 1 .1 9" Dis placeme nt..........3.2 cu. in. 4 .7 cu. in. 3.2 cu. in. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 320 10 Low Air Buzzer Switch Line 5 A ir Intake 22 D rain Valve 6 Governor 11 Air Gauge 17 Air Tanks 23 Safety Valve -2344 Figure J— Schematic Diagram of Typical Air Brake System CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 321 P e d a l S t o p S c r e w P e d a l Figure 2 —Brake Pedal and Application Valve Installed (Conventional Cab—Typical) Figure 3 —Brake Pedal and Linkage IT ill Cab) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 322 R o l l e r P i n B o l t T -6124 -7 5 8 3 T r e a d l e t p m Figure 5 —Brake A pplication Valve Installation Figure 4—Brake Treadle Installation CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 323 . t h e s l a c k a d j u s t e r h e l d m i n i m u m t h a t CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 324 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 325 " S e r v i c e a b i l i t y T e s t s . ” CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 326 , l e a v e d r a i n c o c k s o p e n Figure 11 —Divided Air Tank Figure 12—A ir Tank Check Valve CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 327 Figure 13—Safety Valve a n d r e p a i r r e p l a c e w i t h n e w v a l v e . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 328 , t h e r e b y o p e r a t i n g CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 329 T h e a p p l i c a t i o n v a l v e m o u n t e d s u p p o r t CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 330 T e s t o p e r a t i o n o f b r a k e s . p o r t . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 331 , t u b e s , a n d m a l e CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 332 . t h i s f a i l s c o r r e c t CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 333 , f o r t h e f o l l o w i n g p u r p o s e s : CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 334 C h e c k f o r l e a k s a n d o p e r a t i o n b r a k e s . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 335 . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 336 . C o n n e c t a i r l i n e s . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 337 , u s i n g s o a p s u d s . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 338 - h a l f t h e a m o u n t CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 339 _____ — ■ d / Air Tank DRY ROAD POSITION Limiting—Quick Release Valve Inlet Valve Valve Carrier Front Brake Chambers SLIPPERY ROAD POSITION TPM-6583 Figure 19—Front Brake Limiting and Two-Way Control Valve Operation CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 340 C a m R o l l e r -1584 A n c h o r P i n B r a k e S h o e Figure 20—Front Brake Assembly (Wagner) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 341 " B r a k e A d j u s t m e n t s . " CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 342 B r a c k e t L o c k R i n g B r a k e S h o e L i n i n g Figure 2 2 —Rear Brake Assembly (Wagner) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 343 , S A F E T Y P R E C A U T I O N . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 344 , s c r e w s t h e a d j u s t i n g b o l t . T h e CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 345 . s p i d e r h o u s i n g . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 346 D i s c o n n e c t a i r l i n e s f r o m c h a m b e r s . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 347 , a n d r i v e t s m u s t CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 348 25 Washer 26 Cotter Pin 27 " F ailsa fe” Air Chamber 28 Standard A ir Chamber 29 Lock W asher 30 Nut T-6916 Figure 30—Stopmaster Brake Components (Automatic Adjuster with “ Fail-Safe") CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 349 2. Slide wedge spring off wedge. 3. Rem ove wedge retainer w asher and r o lle r s Figure 32—Installing Seal on Anchor Plunger from r o lle r retaining cage. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 350 ­ placed. T-2340 . Inspect plunger s e a l for any cracking or deterioration. Any deterioration is unacceptable Figure 35—Installing Wedge Assembly and s e a l should be rep laced. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 351 ­ spring co m p ressed . When a ir p r e ssu r e is relea sed le a se bolts are backed out (counterclockw ise) as CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 352 No leakage is p e r m issib le at either lo c a ­ If leakage o ccu rs, replace O -ring with new part. tion. If leakage o ccu rs at clamping ring, tighten CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 353 "strap" type wrench to rem ove p re ssu r e Figure 39—Compressing “Fail-Safe” Power Spring housing from cap a ssem b ly. See fig u res 41 and 42 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 354 Slightly dry with cloth. worn spots may be rem oved with crocus cloth. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 355 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 356 HSG. LOCK GROOVE) POWER SPRING ” RING RELEASE BOLT PISTON SEAL OUTER SNAP RING BEARING WASHER *— WASHER SCREW HEX NUT RUBBER SEAL SQUARE NUT "O ” RING T-6919 Figure 45—Super “ Fail-Safe” Components CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 357 10. A ssem b le cap a ssem b ly, spring, and piston. 18. R em ove "E" ring and inner w asher from r e le a se bolt. C om press assem b ly in fixture (fig. 46). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 358 Remove nut and r e le a se stud from its storage p lace on cham ber body. Remove spring STUD, NUT, AND WASHER INSTALLED (SPRING COMPRESSED) Figure 4 9—Spring Compressing Assembly Figure 4 8 —“ Anchorlok” Brake Chamber Installed CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 359 . Rem ove nuts and lock w ash ers from mount­ 7. Check operation of brak es. ing studs. . Check for a ir leak s. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 360 . Brake shoe anchor pins frozen . F ree up, replace or lubricate as n ecessa ry 9. Foot control valve linkage im properly adjusted 9. Adjust 10. Lubricate or replace 10. Camshaft bushings binding or worn CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 361 4. Open or leaking r e se r v o ir drain cocks. 4. C lose, repair or replace. 5. D efective com p resso r governor 5. Repair or replace CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 362 1. Safety valve out of adjustment 2. See chart on "A ir p ressu re above norm al . P r e ssu r e in system above normal 3. Governor out of adjustment 3. Adjust CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 363 3. Replace seal; clean and lubricate actuation parts 4. Adjusting bolt threaded into actuator too tight 4. Back off bolt 1/ 4 turn 5. Plunger guide w asher om itted 5. Replace w asher CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 364 4. Improper wedge adjustment 5. R eplace sea l and clean and lubricate actuation 5. Plunger se a l failure parts . Reline brakes and check se a ls . G rease on linings CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 365 N ote (2): Used on following m odels: HI, H N , Jl, M H , M I90; FC, FH, FI, FN90; D C, D H 90 with SQ H D and SSHD axles; Dl, D N 90 with SQ H D axle. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 366 9 W asher T-6708 rem oved. 10 Adjusting Nut 3. R em ove nuts from locating bolt, then r e ­ Figure 1 —External Contracting Band Parking Brake m ove bolt. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 367 Move outer end of screw d river away from drive Figure 2—Internal Expanding Type Brake Adjustment shaft. Continue adjustm ent until sh oes are tight CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 368 R elay L ever end of adjusting sc r e w and in sta ll adjusting screw TPM-8399 socket. 2. In sert adjusting screw between adjusting Figure 3— Internal Expanding Type Brake Installed CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 369 4. Install adjusting nut and lock nut. Adjust ____R e ta in e r___________ 17 Tie Rod_____ tp m -?«9 brakes as directed under "Tru-Stop Brake Adjust­ Figure 4-Tru-Stop Type Parking Brake ment." CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 370 T his chamber in "AIR BRAKES" (SEC. 5B) of this manual, incorporates a sprin g applied, air p re ssu r e r e - CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 371 3" 3" 314" 214" 3" Lining Thickness....... 3 /l6 " Ms" 5 /l6" 5 /ie" Va" y«* " Total Lining Area (Sq. In.)..67.5 81.0 99.1 126.0 83.8 44.2 60.7 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 372 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 373 9 Oil Drain Back Holes 17 Balance Shaft Idler Gear 5 Rocker Arm Shafts 10 Oil Filter 18 Balance Shaft Gear 11 Oil Pump Inlet Screen 19 Balance Shaft T-2187 Figure 1 —Engine Lubrication System CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 374 C ylinder Head B olt Torque and Cooling System I n s p e c t io n ........6 K 4 Valve Lash A d j u s t m e n t s ....6A-5 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 375: Spark Plug Removal

    Remove equipment as required to provide open position , operate sta rter with rem ote control a c c e s s to ignition distributor, spark plug w ires sw itch. and coil. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 376: Battery And Battery Cable Service

    Ventilation System " later in this section for in­ v o lts when engine is being cranked, or if cranking structions for serv icin g ventilation v a lves. speed i s low, a weak battery, defective starter CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 377 INSPECTION AND UNIT REPLACEMENT CARBURETOR IDLE SPEED AND Rem ove rocker arm cover from each cy l­ IDLE MIXTURE ADJUSTMENTS inder head. R efer to ENGINE FUEL SYSTEM (SEC. 6M) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 378 R efer to Next Page For G asoline Engine Tune-up Specifications. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 379 12. D isconnect a ccelera to r and choke con­ Engine installation is accom plished by r e ­ tr o ls from carburetor. versin g "Engine Removal" procedure, meanwhile 13. D isconnect tachom eter drive (when used). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 380 REPLACEMENT Same instru ction s apply to either the right- hand or left-hand cylinder head. The valve lifte r s cannot be rem oved until CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 381 0.012 inch. After valve clearan ce adjustment R em ove rocker arm co vers, referrin g to made, in sta ll rocker arm cov er using new in stru ction s previously given. gasket. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 382 9 Cylinder Head 4 Valve Spring 5 Valve Spring Cap Figure 10—Sectional View of V6 Engine Figure 9—Use of Special Tool for Replacing Cylinder Head Assembly Valve Spring without Removing Cylinder Head CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 383 20 to 25 foot­ 9. Start engine and when norm al operating pounds torque. tem perature is reached, check valve la sh . C lea r­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 384 Figure 12-C ylin d er Head Bolt Tightening On som e m odels the crankshaft pulley is not Sequence on V6 Engine readily a c c e ssib le u n less the radiator core is fir st CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 385 1 3 2 b o l t ^ B J L e t a ,n e r ' t 1 § Figure 13—Crankshaft Pulley Removal (Typical) Figure 15—Crankshaft Hub Retaining Ports (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 386 "FULL" mark on dip When installing tube and scre en assem bly on stick . o il pump, u se new gasket between tube flange and CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 387 "Engine O il Pan R e­ placem ent." NOTE: U se gasket cem ent to hold the o il pan Figure 19—Cross Section of Rear Bearing Cap and Seals CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 388 3 Gear and Shaft Assy. 9 Gasket 4 Thrust Washer 10 Bushing (In Housing) 5 Cover and Bushing Assy. 11 Gear Shaft Bushing Figure 21—Removing Seal Upper Half from Block Figure 23—Tachometer Mechanical Drive Components CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 389 To check for proper perform ance of hydraulic governor units the follow ing procedure may be NOTE: N o-load speeds w ill be approxim ately used: 300 rpm higher than indicated fu ll-lo ad sp eed s. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 390 O il F ilter S t u d ..........30-35 Oil Pump to Block B o l t s ......*Oiled with S.A.E. No. 10 Engine Oil. R efer to pages following for Trouble D iagnosis Chart. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 391 3. Clean or replace and adjust spark plug gap. 4. D efective w iring. 4. Inspect wiring and co rrect as required. 5. Ignition out of tim e. 5. Set ignition tim ing. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 392 2. Service air clean er. 3. Carburetor float valve not seating. 3. Clean float valve and set float le v e l. 4. Rich m ixture at idle speed. 4. Adjust carburetor idle m ixture. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 393 1. Adjust idle mixture sc rew s. 2. Improper ignition tim ing. 2. Set tim ing. 3. Vacuum leak (air entering intake manifold). 3. Replace gasket, or tighten manifold bolts. Check and/or replace vacuum brake hose (when used). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 394 3. Drain crankcase and refill to correct lev el. 4. Crankshaft oil se a ls worn. 4. Replace oil se a ls. 5. Pistons and/or rings worn, or pistons damaged; cylinder bores scored or worn. 5. Overhaul engine. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 395 . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 396 Refer to ENGINE MOUNTINGS (SEC. 6D) for engine mounting information. USE ENGINE OIL AS SPECIFIED IN LUBRICATION (SEC. 0) AND SERVICE CRANKCASE VENTILATION UNITS FILTERS REGULARLY. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 398 DESTROY ITSELF AND CAUSE INJURY 2. Fuel lin e s and connections - should be in ­ TO PERSONNEL. sp ected regularly for evidence of leak s. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 399: Checking Drive Belts

    A ir able tune-up sequence, after the engine has reach­ box drains may be cleaned with com p ressed air. ed its norm al operating tem perature. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 400 - 3 R - 3 L - 2 R - 2 L - 1 R T-2 960 co v ers. 2. P la ce fuel shut-down lever in the "NO­ Figure 2 -6 V -5 3 Cylinder Numbering and Firing Order FUEL" position. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 401 When the follow er is too high it w ill bump the tool and should be re se t so Figure 4—Limiting Speed Governor Mounting a ll in jectors are sam e height. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 402 9. Stop engine; in stall the governor cover. The governor cover should be placed on the housing Figure 6—Positioning the Injector Rack Control Lever with the pin of the speed control lev e r projecting CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 403 Figure 8—Adjusting Maximum No-Load Engine Speed (Typical) governor gap. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 404 Start engine and operate at idle speed w hile tool (J-5895) and withdraw the high speed spring observing rpm at tachom eter. and plunger assem b ly (fig s. 8 and 9). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 405: C Ylinder Head B Olt Torque And

    * Threads and bolt heads coated with International Compound #2 (Part No. 5198563). ** With engine running at 600 rpm. Variation between cylin ders not to exceed 25 p si. *** U se in jector tim ing gauge No. J-1853. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 406 14. Rem ove front end sheet m etal, referrin gto SHEET METAL AND FIBERGLASS (SEC. 11) in Figure 12—Access Cover and Floor Panel Removed from Cab ITypical) th is manual for n e c e ssa r y information. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 407 It is p o ssib le, if occasion requires, to rem ove arm shaft brackets to the cylinder head and rem ove or rep lace the exhaust valve springs without r e ­ the brackets and shaft. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 408 ( L . H . ) L o w e r L i n k Figure 13—Use of Special Tool for Removing Valve Figure 15—Fuel Rod and Link Installation Spring with Cylinder Head Installed CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 409 5. Tighten cylinder head bolts about one-half turn in. sequence shown in figure 18. U se torque Figure 17—Installing Cylinder Head on Engine wrench for final tightening of cylinder head bolts. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 410 17. Install rocker arm cover on cylinder head, Figure 18—Cylinder Head Bolt Tightening Sequence u sing new gasket. In stall a ir cleaner. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 411 ­ se a l surface on crankshaft. eter of se a l, tap the sea l assem b ly evenly until Figure 19—Schematic Diagram of 6V-53 Engine Lubrication System CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 412 Oil Pan B olts ..................10-12 * Bolt and stud threads, nuts, and bolt head contact areas coated with International Compound #2 or equivalent. International Compound #2 is available in quart containers - Part Number 5198563. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 413 71 S e r ie s D ie se l Engines section . maintenance m anuals. Crankcase breather tube CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 414 . Too much clearance r e su lts in noisy operation of the engine, esp ecially in the low Figure 1—Adjusting Valve Bridge (71 Series) speed range. CHEVROLET SHIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 415 A ll valves may be lashed in firing order s e ­ quence during one full revolution of the crankshaft Figure 3—Cylinder Numbering and Firing Order (In-Line 6 Cylinder Engine) Figure 5—Adjusting Valve Clearance (Typical) CHEVROLET SERIES 70 90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 416 Figure 6—Timing Fuel Injector (Typical) . Hold push rod from turning and tighten CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 417 4. If n ece ssa r y to adjust, loosen lock nut and To properly adjust governor gap it is n ecessa ry turn id le adjusting screw (1, fig. 7 or 1, fig. ) IN CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 418 This w ill p lace No. 1 or 1L 2. Governor low speed gap closed . injector in the "FULL-FUEL" position. Turn down CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 419 T - 4 2 5 0 Figure 11 —Injector Control Rack Adjustment (V Engine) Figure 13—Checking fnjecfor Rack Spring CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 420 , No. 2 injector rack coupling is too tight. C orrect No. 2 injector rack adjustment by lo o se n ­ ing inner adjusting sc r ew and tightening outer adjusting screw . Figure 14—Idle Speed Adjustment (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 421 53 AND 71 SERIES DIESEL ENGINES 6C-24 Figure 16—Adjusting Buffer Screw ITypical) Figure 7 5—Adjusting No-Load High Speed brake Switch at the governor, in order to make control lev er in the maximum speed position. Turn buffer screw adjustment refer to "Engine Brake" the high speed spring retain er until the engine is la ter in th is section .

  • Page 422: D Ie Se L Engine Tune-Up C H A R T

    N o te 1 : No-load governed speed is approxim ately 150 R P M more than C Y L I N D E R C O M P R E S S IO N ( M i n .) ..............515 P S I * * full-load speed. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 423 Conventional Model (Typical) e n g i n e . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 424 . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 425 11. D isconnect and rem ove air inlet pipe used e n d o f c r a n k s h a f t . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 426: In-Vehicle Engine Component Replacement

    U se new rocker arm cover gasket when in­ w ire connecting sw itch with the term inal under rocker arm cover must be disconnected to allow stallin g cover. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 427 10. Install rocker arm and c le v is assem bly Figure 20—Use of Special Tool IJ-74S5I for Replacing Valve Spring with Cylinder Head Installed on push rod. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 428 11. D isconnect fuel supply line and return p arts, and make inspections and rep airs to cy lin ­ lin e. der head. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 429 (1 6 0 °-1 8 5 °F .), the cylinder head should be squarely on s e a ls and gask ets when tightening c y l­ retorqued; and valve clearance and injector tim ing inder head stud nuts. rechecked. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 430 International Compound #2 or equivalent on cylin­ 13. Rem ove cylinder head bolts, andstudnuts, der head bolt threads and bolt head contact area. then attach lifting equipment, and rem ove cylinder CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 431 Connect all radiator gin es. The damper assem bly is secu red by bolts h o ses and b y -p a ss tube h o ses. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 432 Check gasket area on engine and on front REMOVAL (6-71 ENGINES ONLY) cover. Scrape off any se a le r or gasket portions Drain' crankcase and rem ove oil pan and which may be found. gasket. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 433 (when used). C orrect torque for pulley Installation and Bolt Tightening Sequence retaining bolt is 290 to 310 foot-pounds. Follow recom m ended procedures covering testin g, inspection, and adjustm ents for b est r e su lts. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 434: Engine Sending Units And Switches

    NOTE: Do not u se compound on threads when clo se d . If circu it is energized by turning on the installing unit in oil pan. engine control sw itch, the "Low O il” te ll-ta le light CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 435: Engine Brake (Optional Equipment Item)

    ­ R efer to "Engine Brake Trouble D iagnosis noid valve and engine brake is no longer effective. Chart" later in th is section for p o ssib le cau ses CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 436 - , or -cylin d er engine. 8V -71 engines (fig. 32). The sam e arrangem ent of CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 437 Both ends of w ire must be free to allow w ire to turn with insulator. ENGINE BRAKE COMPONENT INSTALLATION Figure 34—$chematic Arrangement of Engine Brake Electrical Wiring 1. Check valve bridge adjustm ent as directed CHEVROLET SEMES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 438 5. Install o il connector screw and lock nut ■ f ll WIRE ENDS DISCONNECTED TO AVOID DAMAGE FROM TWISTING LOOSENING OR TIGHTENING TERMINAL BRACKET CLAMP REMOVING OR INSTALLING THREADED WIRE INSULATOR Figure 37—Engine Brake Unit Wiring Replacement CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 439 (4), then in stall bolts to attach Figure 39—Torquing Housing Hold-Down Bolls sw itch to bracket. I8V-71 Engine Shown) 2. Connect sw itch w ires to term in als. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 440 BUFFER SCREW SWITCH REMOVAL D isconnect w ires from sw itch term in als fir st, into buffer screw . 2. P osition buffer screw sw itch and bracket , fig. 42). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 441: Engine Brake Trouble Diagnosis Chart

    3. Slave piston clearance adjust­ ment in correct. 4. Engine brake housing o il con­ 4. R eplace defective oil connec­ tor se a ls . n ectors or s e a ls leaking. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 442 1. R eset sla v e piston clearan ce 1. Slave piston adjustment too Engine M isse s or L o ses P ow er. to 0.066-inch a s directed in tight. text. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 443 Fuel Line Nut ..................12-15 F t.-L b s. Slave P iston Adjusting Screw Lock Nut ........15-18 F t.-L b s. Figure 46— Lubrication Diagram (Schematic for 8V-71 N /N E Diesel EnginesI CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 444: Engine L U B R Ic A T Io

    Inlet to oil pump is through a fixed type inlet CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 445 Compound #2 is available in quart containers - P art Number 5198563. The “DIAGNOSIS AND TROUBLESHOOTING” section contained on pages 6C-49 through 6C-52 in this manual, may be used in diagnosing and correcting engine malfunctions in diesel engine models. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 446 This is investigation a re given as follows: CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 447 C om pression p r e ssu r e is affected by altitude lin es purged of air in order for the sy stem to pro­ a s follow s: vide adequate fuel for the in jecto rs. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 448 6-71 30-65 45-70 45-70 drawn into the fuel system ; then, im m erse the end 8V-71 45-70 45-70 45-70 of the fuel return line into the fuel in the container. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 449 A slight p r e ssu r e in the as e x c e ssiv e carbon form ation or foreign matter crankcase is needed to prevent the entrance of dust. in the exhaust sy stem . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 450 When practicability prevents the in sertion of a fitting at this point, the m anom eter 6-71 11.5 8V-71 11.5 may be connected to the engine a ir in let housing. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 451 (or ” p si = 27.7" water vacuum) reading. " p si 2.036" m ercury All Tune-up Operations and Adjustments Should Be Performed Carefully and In Proper Sequence CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 452 IMPROPER VALVE CLEARANCE ADJUSTMENT-Adjust valve clearance. BLOWER NOT FUNCTIONING— Check blower drive shaft and couplings. EMERGENCY SHUT-OFF VALVE PARTIALLY OR COMPLETELY CLOSED-Reset. FUEL AIR LEAKS, FLOW OBSTRUCTION, FUEL PUMP-Refer to “No Fuel or Insufficient Fuel” chart. T-6931 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 453 IMPROPER GRADE AND TYPE FUEL-Refer to Current Diesel Fuel Oil Service Bulletin. DILUTED FUEL— Check storage and handling methods. IMPROPERLY FILTERED OR RESTRICTED FUEL FLOW-Refer to “No Fuel or Insufficient Fuel” T-6932 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 454 3. Low Compression— Refer to “Low Compression” in “Hard Starting’. ’ Blower Air Intake Obstructed— Check and clean air cleaner and air inlet horn and screen. 5. Excessive Exhaust Back Pressure— Inspect exhaust pipe and muffler and replace if damaged. T-6933 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 455 WHITE SMOKE MIS-FIRING CYLINDERS-Check for the following: 1. Faulty Injectors— Replace injectors. 2. Low Compression— Refer to “Hard Starting’. ’ 3. Low Cetane Fuel— Refer to Current Diesel Fuel Oil Service Bulletin. T-6934 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 456 OIL COOLER CORE LEAKING— Replace oil cooler core and use a good cooling system cleaner to remove oil from water passages. ENGINE BLOCK END PLATE GASKETS LE AKIN G— Replace block to end plate gaskets. T-6935 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 457 EXCESSIVE WEAR OF CRANKSHAFT BEARINGS— Change engine bearings, clean oil pan, refer to “Engine Oil Viscosity Chart” for proper grade, and change oil filter element. GALLERY, CRANKSHAFT OR CAMSHAFT PLUGS MISSING-Replace plugs. T-6936 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 458 53 AND 71 SERIES DIESEL ENGINES 6C -61 LOW OIL PRESSURE-Cont. OIL PUMP INTAKE SCREEN PARTIALLY CLOGGED— Remove oil pan and screen, clean oil pan and screen, refer to “Engine Oil Viscosity Chart” and refill crankcase and change oil filter element. RELIEF VALVE NOT PROPERLY FUNCTIONING—...
  • Page 459 Thermostat Housing Vent Holes Plugged— Clean. (2 ) BELOW NORMAL POOR CIRCULATION— Check for the following: 1. Thermostat Inoperative— Replace thermostat. 2. Thermostat Seat Damaged— Replace thermostat. 3. Thermostat Seal Damaged— Replace seal. T-6938 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 460 *T o p S u p p o rt to Lo w e r S u p p o rt Bolts * * T h i s torqu e for standard transm ission. W ith optional Fu ller tran sm is­ sion to rq u e m ust be 300-320 foot pounds. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 461 7 P late (at C rossm em ber) FRAME CROSSMEMBER - T-2756 T-6861 Figure 1—Engine Front Mounting on Figure 2 —Engine Front Mounting on TV 70 Series (6V-53 Engine) Conv. Cab Models I6V-53 Engine) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 462 4. P osition mounting cushions (5) at c r o s s ­ Figure 4 —Engine Front Moufmg on Conv. Cab m em ber ( ) a s shown, then in sert mounting bolts 90 Series (In-Line Diesel Engine) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 463 9 Engine Front Cover NOTE: Key numbers in following text refer to figure Figure 6—Engine Front Mounting on DI, FI90 IVehicles with Air Conditioning) 1. Safely support front of engine, then rem ove CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 464 4. R ev erse the rem oval procedures to in stall brackets an d /or mounting and tighten bolts to torque valves shown on "Engine Mounting Bolt Figure 9—Engine Rear Mounting on TV7Q Models Torque Chart." CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 465 MISSION ON-VEHICLE SERVICE OPERATIONS" disconnected, ra is e r e a r end of power plant using in TRANSMISSIONS AND CLUTCHES (SEC. 7) of c a re to prevent tipping. this manual. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 466 1—Trunnion Type Engine Rear M ountings (Typical) Inspect engine front and rear mountings as part of regular engine maintenance program. Be sure to keep bolts and nuts tightened to torque values specified on chart. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 468 If engine is below operating tem p eratu re, gines. T h erm o stats a re in stalled in top of engine coolant is retu rn ed to suction side of w ater pump w ater manifold. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 469 During engine w arm -up period, action of th e r­ through ra d ia to r and oil cooler, discharging it into m ostat clo ses off the flow of cooling liquid into CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 470 Then the coolant p a sse s down a the th erm o stats open gradually, allowing hot liquid s e r ie s of tubes, w here the coolant tem p eratu re is CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 471: Inspection Of S Y S T E

    (if equipped). sa ry to bring it up to p ro p e r level. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 472: Cleaning S Y S T E

    Install radiator cap firm ly. by the m an ufacturers. However, if ra d ia to r is CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 473 4. If cleaning solution used re q u ire s a n eu tra l­ d ra in plugs. iz e ^ use a s directed by m anufacturer. Figure 6 —Drain Points on 8V-71 Diesel Engine (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 474: Corrosion Prevention

    If cooling medium in system becom es frozen solid, place vehicle in w arm place until ice is into the cooling system . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 475: Water Temperature Indicator

    WATER TEMPERATURE INDICATOR TEST Gauge Figure 9 —Temperature Sending U nit and 1. Disconnect w ire at engine unit. Engine Overheat Switch I8V-71 Diesel Engine) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...

  • Page 476: Engine O Verheat A L A R

    V6 gasoline engines (fig. 7). Figure 10—Temperature Gauge Sending U nit and The 6V-53 D iesel engines have two th erm o stats Engine Overheat Switch (Cummins Diesel Engine) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 477: W Ater F Ilte

    NOTE: Key num bers in text re f e r to figure 15. C lose gate valves at top and bottom of filte r Figure 11—Installing Thermostat (6-71 Diesel Engine) on Alum tilt cab m odels. On rem aining m odels, CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 478: Oil Cooler

    4 U p p er P la te 9 P lu g 5 E le m e n t Figure 15— Figure 14—Water Filter Installed Alum. Tilt Cab Models) W ater Filter Components CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 479: Fan And Drive Belts

    NOTE: Instructions fo r replacing power s te e r ­ Figure 16—O il Cooler Circuit I A ll ing drive belt a re given in "POWER STEERING" Engines Except Detroit Diesel) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 480 ­ 3. Remove front bearing cup in sam e m anner tion. by tapping bearing cup tow ard front of pulley. 4. Tighten pivot bolt and adjusting b o ltfirm ly . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 481 6. In stall flat w asher and bolt. While rotating Figure 2 0 — Separately M ounted Fan Support pulley, tighten bolt to 85 to 95 foot-pounds torque. Assembly Engine) 16-71 (Typical! CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 482: Fan D Rive Hub A Ssem Bly (T Ilt Cab Models)

    8. Clean all p a rts (except bearing) in solvent Figure 2 2 —Fan Drive Hub Assembly (Typical For and wipe dry. V6 Gasoline Engines in Tilt Cab Models) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 483: Gasoline Engines

    Be s u re seal cavity of pump body (6) is com pletely cleaned. Any rem aining old cement could re s u lt in a coolant leak between pump body and se a l assem bly (3). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 484: D Iesel E N G I N E

    1. Open all block d rain cocks and d rain the cooling system . 2. Loosen and rem ove the w ater pump drive b elts. Figure 2 4 —Water Pump Assembly (6V-53 Engine) Figure 2 6 —Removing Pulley (6V-53 Engine) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 485 1. Note the position of the pulley on the shaft with rem over (J-1930). Figure 2 9 —Water Pump I6V-53 Engine) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 486 5. In stall the cover and a new gasket on the pump body. Tighten the cover bolts to 6-7 foot­ pounds torque. 6. If equipment is available, run the pump dry CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 487 Figure 3 2 —Loosening Inner W ater Pump-To-Blower Figure 34 —Removing W ater Pump Drive C oupling A tta ching Bolt w ith Special Tool (J-4242) from Shaft w ith Special Tool (J-1930) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 488 (J-22437) a s shown in figure 36. On c u r­ w ater pump a s follows: ren t engines the end of the shaft m ust be flush with CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 489 A drive g ear is Figure 37— Water Pump Mounting (8V-71 Engine) p re s se d on the opposite end of the shaft. Two ball CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 490 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 491 9. If n ec essary , rem ove w ater seal a s d es­ 7. Loosen the clam ps and rem ove the hose cribed previously under "W ater Seal R eplacem ent." CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 492 P r e s s the g e a r on shaft so it is against the inner studs and nuts to fasten the pump cover to the ra c e of bearing. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 493 Detroit Diesel En g in es..........215 F Cum m ins Diesel Eng ines ..........205 F CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 494 CHEVROLET SERIE5 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 495 POSSIBLY DESTROY ITSELF ANDCAUSE On som e vehicles having paper elem ent, an INJURY TO PERSONNEL. a ir re s tric tio n gauge indicates when elem ent needs serv icin g . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 496 SEAL CAP (Do not remove] screw s 16 to 20 foot-pounds. OUTLET MOUNTING BRACKET CUP ASSEMBLY OIL LEVEL MARK Figure 5 —Oil Bath Air Cleaner ITypical for DieselI Figure 6 —A ir Cleaner (Typical for Diesel) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 497 This ical slo ts, then low er elem ent. Slush elem ent up is a continuous and autom atic p ro c e ss. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 498 This device s e rv e s to w arn that the a ir filte r During cleaning, use extrem e caution so as not is dirty and should be serv iced. The indicator is to puncture o r otherw ise damage p ap er elem ent. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 499 (re fe r to re d ring in the tra n sp a re n t a re a of the body ("SERV- fig. 12). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 500 V erify that ro d end assem bly "A" is th read ed on the cable assem bly %-inch, then r e ­ connect ball joint to relay lev er. 3. D ep ress pedal to %-inch from floor. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 501: Hand T Hrottle A D Ju S Tm E N

    NOTE: A fter replacing filte r elem ent, s ta rt To re p la ce elem ent, tu rn the threaded filte r body engine and check fo r fuel leaks. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 502: Fuel Pump O P E R A T I O

    The p re s s u re should rem ain constant and re tu rn to zero when the engine is stopped. Figure 3 —Frame Mounted Fuel Filter CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 503: Fuel Pump Replacement

    The type c a rb u re to r used on these engines u sed on v ehicles equipped with 401M, 478M en- is the B endix-Strom berg (WWC) ca rb u re to r. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 504 Flooding - In p ractically all c a se s, flooding is caused by a dirty o r sticking float needle and CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 505 Hard or worn leather, distorted spring, stuck vent ball check ★ Pump Inlet Check Ball Out-of-round, damaged seat, stuck ★ ★ Pump Discharge Check Out-of-round, damaged seat, stuck, distorted spring ★ ★ ★ ★ ★ ★ Choke Valve Dirty, damaged, sticking CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 506 3. Inspect the manifold heat control valve (if T-4313 used) fo r freedom of action and c o rre c t spring Figure 7 —Bendix-Stromberg Carburetor (W W C Series) tension. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 507 R eferrin g to fig u re 8, place a 1 /4 -inch open end w rench on diaphragm extension of v ac­ uum idle stop to prevent its rotation while ad­ ju sting plunger. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 508 Use tool (J-4395) to bend float long screw at forw ard side of a ir horn and one Figure 11 —Typical Use of Bending Tool fo Set Float Level CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 509 B endix-Strom berg c a rb u re to rs used on V6 engines. But under no circum stances should they be interchanged with, o r replaced by another type c a rb u re to r. Figure 13—Vacuum Idle Stop Installation CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 510 L o catio n..........Carburetor Throttle Body adjustm ent procedure. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP "» A L...
  • Page 511 F o r s e rv ic e of fuel lin es re fe r to FUEL TANK lu s tra te d in figure 2. AND EXHAUST (SEC. 8) of this m anual. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 512 4. Connect rod assem bly and re le a s e a c cel­ a to r control m echanism a r e identical with eith er e ra to r pedal. Connect pull-back spring. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 513 To adjust With the cab in the driving position, loosen the linkage on all vehicles, re fe r to figure 8 and b ra ck et assem bly "A" attaching bolts, then slide CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 514 ENGINE NORMAL STOP CONTROL ADJUSTMENT (ALL MODELS) The engine stop control is operated by a flex­ Figure 8—Accelerator Control Adjustment ible w ire cable located on the shift co ntro lp ed estal. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 515 Heat generated by the high com pression of a ir Figure 10—Fuel System (Typical fo r “ V " Engines) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 516 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 517 T-6690 fo r identification p u rpo ses (fig. 14). The identifica­ tion tag indicates the nominal output of the injector in cubic m illim eters. Figure 14—Injector Identification CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 518 F rom th is no injection position to full CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 519 9. C lean the ex terio r of the injector with fuel an engine, the filte r caps o r filte rs should not be oil and dry it with co m pressed a ir . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 520 E xcess torque can cause the in jecto r control and forth freely . rack to stick o r bind. P lac e the inj ector in the in j ector te s te r (J - 9787) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 521 ,a s shown in figure 18, until the follow er reach ­ should be checked as follows: es the top of its tra v e l. If the rack does not move CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 522 , check the assem bly of If all the spray tip o rifices a re not open and injecting evenly clean the o rifice s in the spray tip the en tire injector. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 523 One end of this le v e r o p erates against the CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 524 Figure 22—Governor Springs and Levers (8V-71 Engine) lim iting the maxim um engine speed. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 525 The pump circu lates the excess head and a fuel re tu rn line. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 526 "L.H. IN” and "R.H. IN .” These of one minute. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 527 Disconnect fuel tubes from inlet and outlet 3. Connect inlet and outlet fuel lines to the openings of the fuel pum p. fuel pump. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 528 It is im portant that extrem e ca re be ex ercised in the handling and sto rag e of diesel fuel oil, as absolute cleanliness is essen tial to satisfacto ry engine operation. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 529 "C" (fig. 2). Torque the attaching bolts to Figure 1 — Conventional Cab Accelerator 6 to 8 foot-pounds. 3. Rotate le v e r assem bly "B" to full thro ttle an d Throttle Linkage CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 530 4. P ush the knob all the way in and loosen the screw attaching the trunnion to the w ire. le v e r (see fig. 3). Tighten the trunnion screw . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 532 Cum m ins equipped vehicles is the sam e a s covered la te r in th is section. Compressor Compressor Figure 1 —A ir Installation Figure 2 —A ir Installation {Gear Driven) ITypical) (Belt Driven) (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 533 Lubricating oil, under p re s s u re from the en­ the adjusting a rm , the adjusting a rm b rack et, the gine lubricating system , en te rs d rilled crankshaft CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 534 R eplace belt if frayed o r badly worn. S ervice co m p resso r a ir s tra in e r at re g u lar CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 535 2. D isconnect w ater, a ir, and oil lines from c o m p re sso r. 3. Remove bolts attaching a ir co m p resso r Unloader assem b lies on both Bendix-W esting- CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 536 If The following pro cedu re includes disassem bly INSTALLING UNLOADER INSTALLING GUIDE AND PLUNGER INSTALLING UNLOADER PISTON ON UNLOADER PISTON SPRING AND SADDLE Figure 8—Installing Unloader Components (B-W) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 537 , p red eterm in ed m odel. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 538 13 W asher 14 Exhaust Stem Grom m et 15 Piston Valve 17 Valve Spring 18 Piston G rom m et 19 Governor Body -9398 tp m Figure 11 —Compressor Governor (B-W) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 539 Defective governor. SUFFICIENT PRESSURE Unloader line o r cavity to governor re stric te d . D irty intake s tra in e r. U nloader m echanism binding o r stuck. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 540 H V , JV 70 280095 W ater Gear Paper W ater Gear TV 70 280368 90 Series None Dl, FI 282011 W ater Gear N one D H, FH 14 Vi W ater Gear 282013 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 541 . It is m ost im portant, a ir intake filte rs and drive b elts (when used) be serv iced at re g u la r in terv als. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 542 H N /JN -90; D N /FN -90 (F our B atteries) ......1980716 4HR-160 7DR-200 D C /D H /F C /F H -90 (F our B atteries) ......1980718 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 543 4. Hardened b attery plates, commonly called "sulfatio n,” due to b attery being in a low state of charge over a long p erio d of tim e. Figure 1 —Typical Battery with One Piece Cover CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 544 A fter cleaning and installing vent located in the bottom of the vent w ell. DO CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 545 40 to 40 to 50 Amps charged condition during F a st C harge, it can be 50 Amos substantially rech arg ed o r "boosted." In o rd e r to CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 546 These te s te r s have a program m ed te s t p ro ­ cause vigorous gassing. ced u re consisting of a s e r ie s of tim ed discharge CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 547 All celb read less than 1.95 .05 volt difference REPLACE BATTER Y B 0 0 S T-C H A R G E A N D RETEST T-508-1 Figure 3 —Battery Light Load Test CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 548: B Attery S P E C If Ic A Tio N

    10.5 M in. at 300 Amp. 7 DR-200 1980718 10.5 M in. at 300 Amp. 1980760 8DR-205 6.0 M in. at 300 Amp. 1980926 3H-926 2.8 M in. at 300 Amp. 1980974 9H9-974 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 549: Starting System

    CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 550 "W iring D iagram s" booklet to make s u re of is defective and m ust be replaced. p ro p e r connections. Tighten term in al nuts firm ly . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 551 When control sw itch is placed in "IGN" p o si­ sw itch contacts will close to com plete c irc u it to tion and "START" sw itch is energized, c u rren tw ill CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 552 TAKE UP MOVEMENT RETAINER .010" TO .140' PINION CLEA RA N CE TPM-3539 Figure 6 —M easuring Pinion Clearance (Light and Interm ediate Duty) (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 553 The holding wind­ ing also aids the pulling winding. As soon as plung­ e r clo ses the m ain sw itch contacts, pulling winding Figure —M easuring Pinion Clearance (Heavy Duly! CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 554: Starting System Specifications

    Starter-To-Flywheel Housing Bolt V -6 Gasoline Engine M odels ......... 25-35 6-71 Diesel Engine Models..........90-110 6V-53 Diesel Engine M odels Except TV-70..............80-90 TV-70 (only)..............110-160 6V-71 or 8V-71 Diesel Engine Models........110-160 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 555: Ignition System

    On s e rie s 90 Alum. T ilt Cab vehicles, r e ­ move ac cess panel from console to gain access to control switch. Inspecting and adjusting the ignition system CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 556 NOTE: Make s u re d istrib u to r is in good con­ dition and dwell angle is p ro p erly adjusted before Figure 2 —Tim ing M arks IV 6 Engine) ITypical) CHEVROLET SERIES 70-5>0 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 557 2. Remove the ro to r. 2. Connect p rim a ry lead and condenser lead CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 558 NOTE: DISCONNECT AND PLUG VACUUM The point opening of new points can be checked LINE WHEN CHECKING. If the cam angle is le s s CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 559 2. P lace new d istrib u to r to cylinder block Figure 6 —Selling Point Opening (V6 Engine) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 560 Spark plug life is governed to a la rg e extent every 5,000 m iles. by operating conditions, and plug life v a rie s ac - CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 561 S park plugs, to give good perform ance in a SPARK PLUG REMOVAL p a rtic u la r engine, m ust o perate within a certain IMPORTANT: B efore rem oving any sparkplu g , CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 562 Spark plugs which a r e not tightened co rre c tly (3) Plus or m inus one degree. will re su lt in too high an operating tem p eratu re CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 563: G Enerating System G Eneral D E S C R Ip Tio

    F igure 1 shows a schem atic diagram of gen­ F igure 3 illu stra te s a schem atic diagram of eratin g sy stem on vehicles equipped with the two- the generating system used on vehicles equipped CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 564 1119507 tw o-unit type reg u lato r and the Figure 2—Schematic Diagram of AC. Charging Circuit (with Transistorized Type Regulator) (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 565 C ut-out re la y is not re q u ired with A.C. generating able. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK 5HOP MANUAL...

  • Page 566: On-Vehicle Maintenance, Tests, And Adjustments

    On a new vehicle, o r afte r having in stalled p a rtia lly discharged b attery . new b elts, check tension twice in f ir s t 200 m iles CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 567 If light com es on, and open circu it exists Figure 6 —Checking Indicator Lamp Wiring within the reg u lato r. R efer to reg u lato r te s ts la te r. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 568 G enerator output voltage m ust be Figure 8 —Generator O utput Test (Jumper Lead Connections at Regulator) (Except 9000590 Regulator) (Typical) controlled by loading the b attery with a carbon CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 569 W IRIN G HARNESS VIEW C-CHECKING GENERATOR FIELD VIEW D-CHECKING FOR EXCESSIVE CIRCUIT USING OHMMETER RESISTANCE - 1 5 4 7 Figure 9—Using Adapter (J-21600) to Check Generator Output (Full Transistor Regulator) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 570 D isconnect ohm m eter and reconnect the b attery ground s tra p . Closing Figure —Testing Field Relay Voltage g. To check the re g u la to r, connect a volt- Two-U nit Type Regulator (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 571 R eturn variab le re s is to r to the closed o r "no re s ista n c e " position. Figure 13—Testing Voltage Setting (Two-Unit Regulator) d. B ring engine speed up to approxim ately CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 572 "no phones (if available) connected a c ro ss the reg u lato r CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 573 7. F o r an overcharged b attery , low er voltage setting by turning one notch (counterclockwise) and then check for an im proved battery condition Figure 16—Adjusting Voltage Setting (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 574 4. Remove adjusting a rm pivot bolt and gen­ e ra to r to mounting bracket bolts; then rem ove Figure 17—Generator Brush Replacement (M odel 1117754) (Typical) g en e rato r. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 575: Two-Unit Type R Egulator (Model 1119507 O

    3. Remove regulator mounting screw s, then Figure 19—Regulator with Cover Removed rem ove reg u lato r assem bly. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 576 A fter contacts have been cleaned they should be washed with a solvent (non-toxic type) to r e ­ Figure 2 2 —A djustin g Field Relay A ir Gap move any foreign m ateria l. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 577 TR-1 to "F " term in al on the reg u la to r and on through the g enerator field winding to ground, Figure 24—Transistorized Type Regulator (Typical) com pleting the c irc u it back to the battery . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 578 (POS) term in a l on reg u lato r and (NEG) voltm eter REGULATOR INSTALLATION lead to ground on re g u lato r. IMPORTANT: Make su re one b attery cable is 2. Adjust engine speed to approxim ately 1500 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 579 When ignition o r engine control sw itch is c lo s­ ed and engine is not running, the field relay wind­ PANEL BOARD ASSEMBLY Figure 25—Full Transistor Type Regulator Figure 26—Regulator with Bottom Plate Removed CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 580 ­ 4. Note the in su lato rs between the tra n s is to rs ing screw s. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 581 . H i g h s y s t e m v o l t a g e . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 582 FIELD-DISCHARGE DIODE (D3), (Part F, F ig. 29) R eplace the diode if both readings are z e ro , if Figure 30—Checking Regulator Circuits both readings are infinite, or if both are identical. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 583 The the panel board at one end, m erely connect an ohm - silic o n e g re a se in c r e a se s heat conduction. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 584 ENGINE ELECTRICAL 6Y-43 TROUBLE ANALYSIS CHART CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 585 ENGINE ELECTRICAL 6Y-44 TROUBLE ANALYSIS CHART (CONT.) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 586: Charging System Trouble A Nalysis C H A R

    1115841 field relay or to "R” term inal of generator on vehicles equipped with the 1115827 field relay. If voltmeter reading was obtained, field relay is defective. Remove relay and replace. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 587 Rated Hot O u tp u t..........................( a )lf generator output is checked w ithout a regulator, the output should be 5 - 1 0 % higher than the value given. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 588 Fro n t B ra c k e t.............................. Bolt 40-50 T ilt Cab M o d e ls ..............................Bolt 40-50 W ith 1 3 0 -A m p . G e n e ra to r............................CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 589: G Enerating System S P E C If Ic A Tio N

    7— Standard 75-Amp. Integral Type to the stator windings. A capacitor, or condenser, Generator Installed (Typical) mounted in the end fram e, p rotects the r e c tifie r CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 590 ENGINE ELECTRICAL 6Y-49 STATIONARY FIELD COIL (BRUSHLESS CONSTRUCTION) I f * ROLLER BEARING BEARING WELL — COVER GREASE ' - t — RESERVOIR SEAL DIODES Figure 2—Cross Section of 75-Amp. Integral Type Alternating Current Generator (Typical) 2. N ever operate the generator on an open c ir ­ bridge and the diode trio from high voltage and cuit (field term inal connected and output term inal su p p r e sse s radio n oise.
  • Page 591 5. Check battery electro ly te le v e l and sp e cific th erein induces voltages in the stator windings. gravity. R eplenish electro ly te le v e l a s n e ce ssa ry . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 592 Once the regulator turns on, it w ill rem ain turned on until the engine is stopped. Rated Voltage Figure 6—Generator Output Test Connections The generator output preferably should be CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 593 A lso, rem em ber that if the battery Figure 7—Generator End Frame with Cover Removed (Typical) state of charge is low, the regulator may CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 594 (Omit for overcharged battery) (CHECK FOR OPENS) To check the diodes and stator, rem ove the Figure 8—Electrical Checks (Typical) th ree nuts, the th ree regulator lea d s, the three CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 595 GENERAL DESCRIPTION Two brushes carry current through slip rings to c o ils which a r e wound concentric with the rotor This generator, used a s optional equipment shaft. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 596 If te st s t ill is not sa tisfa cto ry , perform other te st or vib rates e x c e ssiv e ly , it should be rem oved for outlined following to locate trouble. inspection and rep air. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 597 ENGINE ELECTRICAL 6Y-56 and regulator is faulty. R eplace regulator a s d es­ EXTERNAL A. C. TERMINALS cribed la te r in th is section and re-ru n output te st. CAUTION: DO NOT short or ground F- BRUSH F+ BRUSH generator terminals.
  • Page 598 3. To check fo r ground, p lace one ohm m eter Figure 12 —Stator Winding Continuity Test (Typical) or te s t lamp prod on c a se and the other te st lead CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL...
  • Page 599 Generator to A d ju s tin g A rm B o lt......................................... 55-65 A d ju s tin g A r m to Engine B o lt..........................................25-30 Pu lle y-to-G e n erator N u t ..............................................55-60 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 600 T here m ust be no mentioned conditions. binding in the linkage. CHEVROLET SERIES 70-90 HEA' Y DUTY TRUCK SHOP MANUAL...
  • Page 601 SET SCREW CONTROL ISLAND PROP SHAFT TYPE SHIFT MECHANISM REMOTE CONTROL ASSEMBLY PROP SHAFT TYPE SHIFT TUBE SHIFT CONTROL ROD T-6702 Figure 2—Tilt Cab with One-Piece Shift Rod (90 Series) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 602 If sh ift controls at control island panel becom e D isa ssem b ly worn or damaged, make rep airs as d escrib ed in NOTE: Key numbers in text refer to figure 4. the following text: CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 603 60-65 foot-pounds and in stall new lock m ove u n iversal joint assem b ly from sh ift rod (24). w ires to pivot scr ew s. 5. Rem ove attaching parts from housing end CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 604 . Check for fr e e m ove­ or drive new o il s e a ls into b ores of end cover and ment in shift m echanism . housing. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 605 5. Adjust tra n sm issio n shift control linkage as m issio n attaching p a rts, then rem ove assem b ly d escrib ed p reviously under "Linkage Adjustment." from veh icle. CHEVROLET SERIES 70*90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 606 (34) and cap sc rew (35). Tighten screw housing (33). Tighten nut (16) firm ly. firm ly. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 607 3. P la ce a clean shop tow el over tra n sm issio n 5. Adjust tra n sm ission control linkage as opening to prevent entry of dirt or other foreign describ ed previously under "Linkage Adjustment." m aterial. CHEVROLET 70-90 HEAVY DUTY TRUCK SHOP MANUAL SCRIES...
  • Page 608 2. Rem ove se le ctio n lev e r (11) from selectio n sc re w to 25 foot-pounds torque and secu re with cam and stud assem b ly ( lock w ire. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 609 Spicer 5752C (When Used on TV70) . . . 37° A ll Other Spicer T r a n s m is s io n s .... 15° Figure 1 Type Remote Control Assembly 0—Rod Tighten clamp nut firm ly. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 610 3. P la ce a clean lin t-fr e e cloth over the tra n s­ m issio n opening to prevent the entry of dirt or Figure 12—Prop Shaft Type Remote Control Assembly other foreign m aterial. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 611 In stall s e t­ 3. Adjust tran sm ission control linkage as d es­ sc r e w (24) in inner shift finger. cribed p reviously under "Linkage Adjustment." CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 612 . b. To low er shift point, lengthen rod (H) by should allow downshifts at highest rpm p o ssib le. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 613 IVz turns, in stall c le v is pin, tighten jam nut, and p roperly located or operating, adjust linkage as sec u r e with cotter pin. follow s: Figure 14—Accelerator and TV Linkage (Allison Transmission) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 614 1 /1 6 -in ch 3. With neutral safety sw itch push rod prop­ clearan ce between push rod and m aster cylinder erly adjusted, tighten jam nuts secu rely . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 615 2. Holding the retard er pedal in this position adjust the stop bolt "A" until it touches pedal as shown. R e le a se the pedal and tighten lock nut against m a ster cylinder. Figure 19—Retarder Controls (TM80) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 616 . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 617 If the units are walking out of gear it could sh afts, joint angle, rear a xle, d ifferen tials, etc. be caused by: a. Im proved highways perm it sustained high a. Interference or resista n ce in the shift CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 618 Worn synchronizer com ponents with the lo s s 1. Sliding gear tight on shaft sp lin es. of clutching action a re usually caused by poor CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 619 "S.A.E. #2" type flyw heel housing a s shown in fig ­ ure 1. The "Apron" type flyw heel housing is easily The required operations w ill be obvious upon identified by the sh eet m etal pan which co v ers the CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 620 2. Shift the tran sm issio n into high gear. 3. Mount tran sm issio n on dolly or jack and m ove into position under the v eh icle. Figure 1 —Flywheel Housing Identification CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 621 DC, DH, DN 90 R T 0913 V iew C, Fig. 5 assem b ly . DI 90 RT0913, View D, Fig. 5 18. On tilt cab m odels, reconnect shift control CHEVROLET SERIF-S 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 622 If this condition e x is ts, m easure the total gap Figure 4 —Transmission Rear Mounting IConv. Cab with RT 09 J 3, except HN, JN 90) betw een the le ft- and right-hand sid e s and divide CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 623 However, it m a y b e n e c e s- m ent, e tc ., on som e v eh icles to provide clearance CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 624 C arefully m ove tran sm issio n assem b ly toward engine so studs can enter h o les in flex plate and so that pilot on tran sm ission en ters pilot hole in center of flyw heel. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 625 NOTE: O il return p a ssage in rear bearing cap put yoke or companion flange off m ainshaft. m ust lin e up with o il p a ssa g e in tran sm ission ca se . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 626 With the control button up the control valve is With the sp litter le v er on the sp litte r control clo sed and a ir is rem oved from end port of air CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 627 To check the air sy ste m and pin-point the the tra n sm issio n and v ice v e r sa (co rrect as trouble area , the following procedures a re reco m ­ n ecessa ry ). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 628 4. If the a ir sy ste m op erates in co rrectly , th is be 57.5 to 62.5 p si. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 629 RETAINING yRED LINE BLACK LINE GASKET G REEN LINE T-6665 AIR INLET FILTER ELEMENT Figure I0 —RT0 913 Air Controls (Tilt Cab Models) Figure 11 —Fuller Transmission Air Filter CHEVROLET SERIES 70-90 HEAVY DUTY TRUCl>. SHOP MANUAL...
  • Page 630 SPARINGLY, with silic o n e fluid lubricant p rior to 1 0 ,0 0 0 often under high humidity conditions. assem b ly . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 631 2. Install new gasket and adapter plate on 1. D isconnect a ll a ir lin e s from the a ir valve. tra n sm issio n c a se . U se gasket cem ent SPARINGLY CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 632 R em ove sh im s to low er a ir p r e ssu r e . One dry with a clean lin t-fr e e cloth. shim is equal to approxim ately p si. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 633 2. R em ove cover from shift cylinder. 3. R em ove ela stic stop nut retaining piston to tro l valve is open and air p a sse s through to the shift bar. shift cylinder cover. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 634 Constant, regulated a ir is channeled through the cover to the front sid e of shift piston - a ir is Figure 17—Splitter Shift Cylinder alw ays on th is sid e of piston. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 635 Hand brake (when used) and speedom eter lev e r and shift rods on the tran sm ission in "NEU­ drive are at rear of tran sm ission . TRAL." Figure 1 —Rod Type Auxiliary Transmission Linkage CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 636 There must be no binding tran sm issio n power tak e-off (when used). in the linkage. 7. P osition a suitable dolly or jack under the NOTE: Due to the construction of internal CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 637 MOUNTING PLATE FRAME FRAME MOUNTING FRONT MOUNT BRACKET VIEW C-FRON T MOUNT SPICER 7041 AUXILIARY TRANSMISSION FRONT— VIEW F-FRO N T MOUNT (TYPICAL ALL MODELS) T-670« Figure 3 —Auxiliary Transmission Front Mountings CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 638 Specifications) REAR MOUNTING FRAME BRACKET 70-80 FT. LBS. VIEW E -R E A R MOUNT SPICER 8341F AND 8345F VIEW D -REAR MOUNT SPICER 7041 T-6707 Figure 4 —Auxiliary Transmission Rear Mountings CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 639 SP8552 SP8 341 V ie w E V ie w E l l/8 D H 9 0 ..................8 V -7 1 SP8554 V ie w E V ie w E SP8345 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 640 2. Move the r e le a s e fork to a position w here and adjusting nut. 4. Connect p ull-back spring to the r e le a se fork, then check operation of clutch linkage. Figure 1—Mechanical Clutch Linkage (HM, JM 80) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 641 M ost m aintenance personnel u se the clutch Rem ove block from clutch pedal. pedal " free-travel" or "free-pedal" m ovem ent as CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 642 5. U sing large end of tool worn bushings, shafts, o r linkage arm s. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 643 9. When sa tisfied that internal clutch adjust­ rem ove r e le a se bearing OUT or away from fly - ment is co rr ect, in stall adjusting ring lock. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 644 M ovement of piston is transm itted a s stated following: CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 645 P urpose of m aster cylinder push rod adjust­ flooring a s shown in figure 10. A c c e ss to pedal ment is to ensure full return of m aster cylinder linkage for checking and adjusting purposes is CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 646 0 to 1 /1 6 -in ch clearance Figure 14—Master Cylinder Push Rod Check betw een push rod and m aster cylinder piston. After and Adjustment CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 647 A fter making adjustm ent tighten lock nut firm ly . Fig. 16—Clutch Master Cylinder Installed (Steel Figure 18 —Push Rod Clearance Checking Tool Tilt Cab Models, Except TM 80 and TV 70) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 648 (fig. 20). B ack off adjusting nut until the tool just fits be­ tw een the nut and wedge. Figure 2 0 —Using Large End of Tool CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 649 6. U se a la rg e screw d river to turn adjusting r e le a se bearing and yoke (free-travel) should be ring. 1 /8 -in c h as shown in figure 5. U sing sm a ll end of CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 650 R e­ sp ec ia l cover (J-8554). Connect p r e ssu re tank place all damaged or worn item s. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 651 (11) after rem oving attaching bolt (9). A fter installing new bushings it may be n e cessa r y CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 652 The clutch ind ers is designed to vent the fluid r e se r v o ir w ith- cylinder does not u se a residual lin e p re ssu re CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 653 3. P edal binding on shaft, preventing full r e ­ For bleeding brake sy ste m refer to 'HYDRAULIC turn of p iston — fr e e up and lubricate pedal. BRAKES" (SEC. 5A) of this manual. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 654 "Bleeding Hydraulic 3 Cylinder Body 7 Piston System ." 8 Piston Seals «•» 4 Push Rod Boot MASTER CYLINDER REPAIR The follow ing procedures cover d isassem b ly, Figure 27—Clutch Slave Cylinder CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 655 3. R em ove b o lts retaining sla v e cylinder at fitting. See "Bleeding System " p reviou sly in this mounting, then rem ove cylinder assem b ly. sectio n . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 656 "Clutch Installation." quantity of high tem perature g rea se. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 657 4. Slide r e le a se bearing and support assem b ly CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 658 A lso , lubricate clutch c r o ss shaft bushings, using fitting at each sid e of clutch housing. PILOT BEARING Figure 4—Clutch Cover Hold-Down Bolts C orrosion or roughness on either the ra ce or (Lipe-Rollway Clutch) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 659 R eplace if the above conditions are evident. th ese m arks. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 660 PEDAL GRADUALLY TRAVELS DOWNWARD . Overhaul m aster cylinder. 1. Clutch m aster cylinder leak s past prim ary cup. .2. Tighten all line fittings and check for leaks 2. External leaks. in line. -6847 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 661 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 662 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 663 P r o g r e ssiv e ly tighten all cap sc r e w s to d rive p ins. 35-40 foot-pounds torque. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 664 . If they do not, r e ­ "CLUTCH CONTROLS" (SEC. 7D) of th is manual. NOTE: R efer to follow ing page for "Troubleshooting Spicer Clutches." CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 665 3. Clutch r e le a se bearing housing striking flyw heel ring. clutch housing bushings and r e le a se yoke fing­ e r s . If badly worn, replace p arts. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 666 The front end drive PTO (power take-off) is opening hood. For serv icin g a ll front end sh eet driven directly from the hub on front of the crank­ Figure 1—Front End Drive Power Take-Off (JM 80) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 667 PTO drive shaft assem b ly D isconnect or rem ove front end mounted and co rrect, a s n ec essa r y . Check for proper oper­ power take-off. ation of unit and controls. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 668 The follow ing procedure for draining fuel from Figure 1—Tank Siphon Construction CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 669 , the couplings w ill leak. The tubing m ust be double-lap flared at the Figure 3 —Single and Double Lap Flare ends in order to produce a strong leak -p roof joint. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 670 In stall ram and tap lightly until fa ce of punch contacts fa ce of die blocks to Figure 7—Teflon Hose Assembly com plete f ir s t fla re operation (fig. 5). CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 671 . Set Figure 9—Proper Installation of Teflon Hose the sle e v e barbs into the teflon tube by pushing a CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 672 Installation of undersize or oversize hose support clamps must be avoided.______________________ 9. Tighten the fitting connection and clam ps. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 673 B a se can then be rem oved over the rheo­ shown on Wiring D iagram in "Trouble D iagnosis sta t and float. Chart” la ter in this section i s connected a c r o ss CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 674 Teflon Hose Fittin g s ..............Tighten Fittings O n ly Sufficiently to Prevent Le ak in g . R efer to Next Page For "Fuel Gauge System Trouble D iagnosis Chart." CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 675 * Ignition sw itch m ust be "OFF" before rem oving tank sending unit, otherw ise full battery voltage may d e s­ troy unit or ignite fuel vapors. F or maximum safety, rem ove cable from negative battery term inal. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 676 C rossover and Strap) 13 U-Bolt 20 Clamp 5 Bolt 14 Exhaust Pipe 21 Tail Pipe Spring 15 Flexible Coupling 7 C rossm em ber Figure 1 —Horizontal Muffler and Vertical Tail Pipe ITypical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 677 6 M uffler to A ir C leaner Tube 21 Exhaust Pipe Clamp A ssem bly 14 Support Clamp 22 C rossm em ber T -6117 Figure 2 —Vertical Muffler and Tail Pipe (TypicalI CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 678 The weight of the exhaust sy stem should be prop- CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 679 E lectrica l System is functioning properly. WARNING - CARBON MONOXIDE Keep cowl vent and heater intakes clo sed when operating in congested traffic to prevent deadly exhaust g a se s from entering cab. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 680 Pitm an arm by linkage co n sist­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 681 9 Lock Washer Pitman Shaft Sector Gear Ball Guide 10 Pitman Shaft Ball Nut 11 Pitman Shaft Oil Seal Worm Shaft *Some Models -6900 Figure 1 —Type 553-D and 555-D Steering Gear (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 682 25 Lash Adjuster Washer 9 Back-up Adjuster Lock Nut 26 Pitman Shaft 10 F iller Plug 27 Drain Plug 11 Worm Upper Bearing - 2 9 5 3 Figure 2—Type 568-D Steering Gear (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 683 D isconnect drag link, id ler link, or con­ necting rod from Pitm an arm . Note relative p o si- Figure 6—Steering Gear Adjustment Points Figure 4 —Checking Steering Wheel Rim Pull (Typical) (Type 568-D) (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 684: Steering Linkage

    Rem ove cotter pin and nut from each end of cribed in FRONT SUSPENSION (SEC. 3) of this the drag link. D iscard cotter pins. manual. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 685 NOTE: This initial tightening w ill fit the taper­ bolt, then rem ove the end assem b ly. ed studs snugly and prevent m ovement when nuts 2. At socket end of drag link, rem ove end a re torqued. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 686 If w ith w heels in the straight-ahead position. C lear­ connecting rod b ecom es worn or damaged, replace ance around the ball stud should be uniform . If CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 687 (if used) over each ball stud. Install a ball stud nut on each stud and tighten firm ly to Figure JO—Steering Linkage (TM80) (Typical) sea t the tapered stud. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 688 "Specifications" at end of th is section, then ad­ dust cork shield ( ), and dust cork spring (3) on vance to next hole and in stall new cotter p in s. tapered stud in order liste d . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 689: Steering Wheel And Steering Column

    2. Tap steerin g wheel gently into place. 3. In stall w asher and steerin g wheel locking Figure 12—Steering Wheel Removal ITypical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 690 The quick r e le a se , adjustable steerin g column, sc r e w s. Tighten screw s to 20 to 30 inch-pounds on Alum. T ilt Cab M odels covered by th is manual, torque. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 691 4. Remove bolt attaching clamp yoke on s te e r ­ Figure I S —Steering Column and Shaft Components (Conventional Cab Models) (Typical) ing shaft to steerin g gear worm shaft. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 692 2. Rem ove two screw s which attach hazard se a t, and spring from the o n e-p iece steerin g shaft; warning sw itch to housing and three screw s which CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 693 BEARING ASSEMBLY DIRECTIONAL section . HOUSING T-4433 NOTE: Adjust the "stop" clamp toallow 0.005" (min.) to 0.030" (max.) axial m ovem ent of shaft Figure 19—Directional Signal Control Assembly (Typical) assem b ly. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 694 STEERING COLUMN AND 9. Connect directional signal and hazard warn­ UPPER SHAFT DISASSEMBLY ing lighting w iring connector to m ultiple connector 1. R em ove directional sign al control lever; under dash. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 695 (1) and two cork w ashers (3) fa ll off the w asher on center c r o ss (4) and retain with snap center c r o ss (4). ring ( CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 696 29 Bolt 30 Column Support Bracket 9 Nut 31 Upper Shaft 10 Washer 32 Spring Dust Cover 33 Column Housing 12 Spacer 1-6259 Figure 23—Steering Column and Shaft Components (Alum. Tilt Cab) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 697 5. Position center c r o ss on upper shaft yoke TH ESE PARTS. in interm ediate shaft tube yoke. Install two new CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 698 "Steering Wheel Replacem ent." e r s, and lock w ash ers. 2. Scribe an alignm ent mark on low er ste e r ­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 699 "Steering Column Upper B earing R eplacem ent.” 5. Position cap over rubber lin er, being ca re ­ 3. Rem ove four sc r e w s and w ash ers which CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 700 ­ r a ce, of the bearing with a long punch, from the vent internal steerin g shaft joint in terferen ce. opposite end of the housing. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 701: Mechanical Steering Gear Replacement

    Tighten bolts to torque . Bend the dust cap retaining tabs into the liste d in "Specifications" at end of th is section . groove. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 702 . 2. P osition Pitm an arm on the secto r shaft, 4. Install cotter pin in connecting link ball nut. being careful to align serra tio n s, and lightly tap CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 703: Torque Specifications

    *T ig h te n to Specified To rq u e , Then A d va n c e to N e x t Alig n in g S lo t and Install N e w C otter P in . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 704 Do not use replacement parts of lesser quality or substitute design. Torque values must be used as specified during reassembly to assure proper retention of these parts. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 705: Power Steering

    R efer to LUBRICATION (SEC. 0) for type of fluid to be used, method, and Figure 1—Power Steering System (Conv. Cab Models) (Typical) intervals for fillin g. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 706 B leed air from the hydraulic sy stem as follows: Figure 3 —Checking Pump Hydraulic Pressure (Vane Type Pump) ITypical) NOTE: When hydraulic fluid is added to power CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 707 P r e ssu r e reading should b. If "Used" belt, position pump to obtain 78 be within lim its liste d under " P ressu re R elief pounds. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 708: Power Steering Gear And Control Valve

    CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 709 19 Valve Body Ring 20 Back-up Seal 21 Valve Assem bly 22 Torsion Bar Cap 23 Back-up Washer 24 Worm Bearing 25 Worm Oil Seal TPM-9060 Figure S —Power Steering Control Valve (Type 553-DV) (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 710: Troubleshooting The P Ow Er Steering Gear

    "Steer­ stan d still parking, with w heels at end of tra v el. The ing Gear Replacem ent." "hissing" n o ise is usually caused by a faulty valve. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 711: Power Steering Hydraulic Pump

    Figure 6 —Power Steering Hydraulic Pump Installed (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 712 (11). If pump p r essu r e ex­ lo o se ly . ceed s a certain predeterm ined p r e ssu r e , the p r e s - CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 713 STEERING SYSTEM 9-34 VIEW A-PUM P OPERATION-LOW SPEED LEGEND DISCHARGE OIL SUPERCHARGE OIL HIGH PRESSURE OIL RESERVOIR AND RETURN OIL RING-ROTOR LEAKAGE OIL VIEW B-PUMP OPERATION-HIGH SPEED T-1166 Figure fi—Power Steering Hydraulic Pump Operation CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 714 In- CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 715 Figure 11 —Pump Operation and Fluid Flow up fo r c e s the spool open against the light spring. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 716 The slip p er-ty p e hydraulic pump is a constant 2. Install caps at pump fittings to prevent displacem ent type pump with a minimum output of drainage of oil from pump. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 717 Installation when le v e l is m ore than two inches below fille r 1. P osition pump and mounting bracket on en­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 718: Troubleshooting The Hydraulic Pump

    D efective se a l or damaged sh aft....R eplace damaged p arts. Leaks in m etal p a rts. . . Damaged ca stin g s.......... . R eplace damaged p arts. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 719 Flow control valve stuck open. Rem ove pump, d isa ssem b le, and clean con­ trol valve. Rem ove pump, d isa ssem b le and repair. Vane or vanes stuck in rotor slo ts. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 720: Power Steering Power Cylinder

    Clean dirt from around hose connections On com pletion of a turn, reduced effort on the at the power cylinder. steerin g w heel allow s steerin g geom etry of the CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 721 "Bleed­ rod guide assem b ly. ing The Hydraulic System ." . Apply a ir p re ssu re to the retraction port Figure I S —Power Cylinder (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 722: Troubleshooting The Power Cylinder

    , the p r essu r e r e lie f valve is not operating properly and the com ­ Chart" at end of this section . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 723: Tie Rod Anti-Rotation Bushing

    (not sidew ays) to elim inate danger of a new a ssem b ly. P roper repair requires the u se of bending fin s. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

  • Page 724: Quick R Eference Troubleshooting Chart

    Replace pum p ring. Ex tre m e w ear of pu m p ring. La p aw ay light scoring. Replace heavily scored parts. Scored pressure plate, thru st plate, and or rotor. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 725 T h ru s t bearing a dju stm e nt too tight. Rem ove gear and a d ju s t to specifications. Stic ky valve spool. Rem ove and clean valve or replace va lve . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 726 T o elim inate the gear, close the gauge valve and qu ickly test pressure of the p u m p only w ith the engine at w arm id le; then open the valve to avoid increasing oil tem perature. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 727 A d ju s t to specifications. socket movement. W orn ball seats. Replace seats. 4. Piston rod end Loose bolts. To rq u e to specifications a fter proper positioning to specifications. clamp movement. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 728 M inim u m P .S .I ..........................1000 M in im u m P .S .I ..........................900 M axim u m P .S .I ..........................1100 M axim u m P .S .I ..........................1000 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 729 ♦Tighten N u t to Specified T o rq u e , Then Ad va n ce to N e xt A lig n in g Slot and Install a N e w Cotter Pin to Secure. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 730 190 to 210 foot-pounds. 5. Retorque nut No. 1 to 190-210 foot-pounds. . Wheel clam ps m ust be seated following Figure 1—Budd Type Wheels Shown w heel circu m feren ce. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 731 S STUD CAST TYPE WHEEL > \ 3 > < 10 STUD © 1 6 STUD CAST TYPE WHEEL figure 3—Wheel Nut Tigfifening Sequence (Casf Type WheelsJ Figure 4 —Wheel Nut Tightening Sequence tDisc Type Wheels) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 732 Figure 5 —Method of Checking for Distorted Wheels se r v ic e under a ll operating conditions to which CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 733 (brake drums, b earings, s e a ls , etc.) are included in the balancing procedure and thereby have any existin g unbalance Figure 6—Tire Rotation Diagram corrected . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 734 . table o il soap. U se a brush or cloth swab to apply. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 735 6280 6590 6870 716 0 7430 12.00-24 6330 6660 6980 7280 7580 7880 N O T E : Underlined Figures Indicate M a xim u m Recom m ended Lo ad . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 736 N O T E : Underlined Figures Indicate M a xim u m Recom m ended Lo a d . LOAD RANGE DESIGNATION LETTER TO PLY RATING NUMBER CONVERSION CHART P LY RATING LOAD RANGE L E T T E R CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 737 WHEELS AND TIRES 10-8 IMPORTANT At regular intervals wheel nuts should be checked for tightness. A noticeable noise vibration could indicate lo o se wheel nuts. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 738 HM and JM 80 M odels which should be CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 739 (fig. 5) is inverted 180 d eg rees. . Rem ove bolt, nut, and w asher which attach each strut rod to sh e ll. Figure 4—Radiator Shell Strut Rods Figure 6—Radiator Shell Flexible Mounting CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 740 2. Remove four bolts and lock w ashers which for replacing the com plete fender assem b ly which attach running board to fram e supports. Remove includes components shown in figure 7. running board. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 741 If n e ce ssa r y , tighten a ll attaching bolts and nuts. loosen adjustable sle e v e clam ps on stru ts, then Figure 9—Hood Center Panel Mounting CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 742 R E A R M O U N T I N G H O O D S T O P G U I D E HINGE STRAP Figure 11 —Hood Stop Cable Clevis Installation Figure 10—Fiberglass Hood Removed ITypical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 743 (fig. 13). L oosen strap b o lts, then Figure 15—Hood Mounting Adjustment at Figure 13—Hood Fqre and Aft Adjustment Cab Cowl IM and C Models ShownI CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 744 An illu strated instruction sh eet is included in in sta ll fender sk ir ts, rev erse above procedure. the com plete Repair Kit No. 1050535. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 745 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...
  • Page 746 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 747 R E M O V E R T O O L T-2259 term inal being careful not to damage connector. P ull w ire and term inal from connector as shown in Figure 2 —Removing Twin Lock Type Connector Terminals figure CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 748 (fig. 3). Figure 3 —Engine Harness to Instrument Panel Figure 4 —Engine Wiring Harness Connector Terminal Harness Connector (Alum. Tilt Cab Models) Identification (Alum. Tilt Cab Models) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 749 S p lic e d C o n n e c to r to E n gine A la r m B u z z e r and Low W a te r T e l l - t a l e ................G rn . W ht. T r , CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 750 Two 12- The headlight and parking light circu its on a ll v eh ic le s are protected by a 25 amp automatic re se t term inal junction blocks are used. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 751 -s e t to ener­ the fu se block is located under left end of dash g ize the e le c tr ica l sy stem . panel. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 752 P o w e r Window (R.H .). M a ste r A ll E x cep t H eadlam p. T-6109-1 Figure 7—Circuit Breaker and Junction Panel (Tilt Cab Models—Alum. Tilt) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 753 . To aid in identification, the gauge Figure 9 —Fuse Block and Circuit Breaker s iz e of the w ire i s labeled on the side of the link. Mounting (Conv. Cab ModelsI (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 754 If speedom eter te st machine that is equipped with a drive. Connect b eco m es inoperative, disconnect cable at rear of Figure 11 —Fusible Link Ammeter Fuses (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 755 D isconnect wiring CHEVROLET SERIES /0-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 756 Figure 13—Accessory Feed Relay Schematic attached to the cab roof panel. A ir p re ssu re to Diagram (Alum. Tilt Cab Models) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 757 E l e c t r i c S p e e d o m e t e r I Q u i c k C h e c k P r o c e d u r e Inoperat ive System D i s c o n n e c t p l u g - i n c o n n e ct o r at rear of s p eedometer.
  • Page 758 I n o p e r a t i v e S p e e d o m e t e r (O d om et er F un ct i o n a l ) D i s c o n n e c t p l u g - i n c o n n e c t o r a t re ar of s p e e d o m e t e r . C o n n e c t o h m m e t e r b e t w e e n "...
  • Page 759 I.C .C . m arker lam p relay oper­ when the engine control sw itch is in the "ACC” or ating co il at term inal No. 3. "IGN" position. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 760 3. Install screw s which attach instrum ent c lu ster to panel, or in sta ll a c c e s s panel cover. 4. Connect negative battery cable to battery, Figure 14—Fuel Shut-Off Solenoid CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 761 The low air p re ssu r e alarm sy stem , on v e­ fie r assem b ly, low coolant control, and a separate h icles so equipped, c o n sists of a low air p ressu re CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 762 1. Low coolant at cold le v e l. Coolant expansion covers Started, then both turn off after engine probe. is run for a few m inutes. 2. D efective probe. 3. D efective control unit. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 763 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 764 5. Check operation of each gauge and unit. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 765 3. D isconnect w ir es and/or lin e from gauge. tion gauge, a ir brake gauge, and the engine oil Rem ove retaining nuts and w ash ers, then rem ove gauge and sp acer from panel. tem perature gauge. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 766 L O W AIR T.T. (WHT.-RED//TR. & BLK.-GRN. TR.) L O W OIL T.T. (PINK & DK. BLUE) L O W W A T E R T.T.(PINK & BLK.) Figure 17—Connections at Rear of Instrument Cluster (Conv. Cab ModelsI (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 767 / ) ) ) r r 7 7 7 7 7 SPEEDOMETER HI-BEAM TELL-TALE (LT. GRN. & BLK.) INST. PANEL WIRING HARNESS T-6714 Figure J8—Connections at Rear of Instrument Cluster (Tilt Cab Models—70-80 Series) (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 768 . The air restrictio n gauge marked "AIR RE­ Two fu se s are used with the am m eter, one in STRICTION FILTER” on the instrum ent panel in­ CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 769 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 770 IMPORTANT: W henever a sealed -b eam unit tional test lam p. has been replaced or after rep airs to front end CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 771 2. Rem ove scr ew s which attach headlamp r e ­ taining ring to mounting ring. U sing a hooked tool, should be made with the veh icle loaded with the CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 772 The parking light circu it is pro­ tected by an autom atic r e se t type circuit breaker Figure 24—Single Sealed-Beam Unit Replacement built into the main light sw itch. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 773 3 candlepower, and the stop light block. On alum tilt cab m odels, the lamp circuit filam ent is of 32 candlepower. is protected by a 5 - amp circu it breaker on the CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 774 Dom e light len s is of molded p la stic with a Figure 26—Dome or Sleeper Compartment Light lug molded on edge of len s at center top and bot­ (Alum. Tilt Cab Models) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 775 Burned out fu se on fu se block or defective Figure 2 8 —Directional and Parhing Lights (Tilt Cab) (Typicall circu it breaker. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 776 33 may be rep laced a s explained under “ D i­ rection al Signal Control A ssem bly" later in this Figure 3 1 —Main Light Switch Circuit Diagram section . (Tilt Cab Models) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 777 A lso, make 4. Check operation of a ll ligh ts. su re w iring connections at sw itch are fully engaged. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 778 2. P osition control le v e r on control assem b ly Figure 34—Directional Signal Wiring Harness and attach with screw . Tighten screw firm ly. Connector (Conv. Cab and 70-80 Tilt Cab) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 779 If directional te ll-ta le on instrum ent panel 2. R em ove control assem bly wiring from the CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 780 H I - B E A M T E L L - T A L E L I G H T ..................Exc ep t Steel T ilt Cab M o d e ls..................Steel T ilt Cab M odels......................667582 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 781 Sealing V o ltag e ............ C O O L A N T L O S S I N D I C A T O R M o d e l....................1596559 CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 782 GROUND - DASH ENG. ' i f — 9 GRD. S T R A P — *J |. DASH > > Figure 37— Cab, Engine, and Chassis Wiring—HI, Jl, MH, Mi-90 Sheet 1 of 7...
  • Page 783 GENERATOR CONTROL SWITCH TEMPERATURE GAUGE Figure 37 —Cab, Engine, a n d C h a s s is W ir in g — H I, JI, M H , M I - 9 0 Sheet 2 o f 7...
  • Page 784 Figure 37—Cab, Engine, and Chassis Wiring—Hi, Jl, MH, MI-90 Sheet 3 of 7...
  • Page 785 -INSTR. LP TAKEOFF CONNECTOR - - 2 0 GRAY AMMETER ( R.PO.) -/8 G R A Y — OIL GAUGE - /8 G R A Y — UPPER LOWER VOLTMETER BEAM UNIT -!8 G R A Y —@^' TACHOMETER P K G L P -1 8 GRAY----- !6 PURPLE- ^ - 1 6 PURPLE —...
  • Page 786 — CD----------R.H. FfiT. DIR. I STOP -TAW. S DlR.LR STOP SWITCH U K STOP TAIL EMERGENCY PARK BRAKE d i r . l p STOPLIGHT SWITCH R.PO. J 7 4 (STD.-MH/MI/CH/tl 9 0 ) T R A IL E R EMERGENCY STOPLIGHT SWITCH R.PO.
  • Page 787 -nar.em.-----© ----------------- - 2 BLK.<RB6ED > — —T " j • +~eau(- v f * ' ' ) * ■ ■ * I A X L E S H F T M T R R E O SL E E V E --- ------ srtio SPCEOO.
  • Page 788 LEGEND C I R C U I T I D E N T I F I C A T I O N SYMBOL JUNCTION FUNCTION TERM. CWITY(* I THRU’ 16) 18 WAY MULTPLE TERM^CT. STUO'tNNER(L.H.) •NSTR. PANEL HARN. TO ENG.HARN- -ENG.COMRARTMENT-OASH PANEL-UPPER RHSCE TERM.
  • Page 789 4 - 6 V BAT. F R A M E - M T D . DU6L-I2V. BA T-FR A M E MTD. R.RO. T 6 8 STARTER STARTER NTERLOCK HORN VOLTMETER AMMETER RPO. U3I WRE WITH RED SLEEVE GENERATOR 3 8 —Cob, Eng F ig u r e i n e a n d C h a s s is W ir in g —...
  • Page 790 CONTROL SWITCH TEMPERATURE g a u g e FUEL GAUGE Figure 38—Cab, Engine and Chassis Wiring—HN, JN-90 Sheet 2 of 5...
  • Page 791 NOTE-LETTERS"A THRU C 'F O R ORCU tT C O N T M JT V ONLY. - 0 WHT. 2 RED — p in k 'A 8 C' ------------- 18 WHT. 2 RED T R .------------ - 18 B L K . GR N . T R . -1 8 B LK .
  • Page 792 — •------------ e Y E L L rL .H D IflL P - --------- g RED -STO P L PS. - S C M T f lL P LU G W M E * * 0 . U 6 7 - ----- GBRfJrTAtL LPS.
  • Page 793 3 S P E E D A X L E A IR O P E R A T E D S O L . A IR V A L U E (TANDEM A X L E ) (T A N D EM A X L E M O D E L S ) HEATER ►...
  • Page 794 LEGEND JUNCTION SYMBOL FUNCTION LO C ATIO N WAY C O N N . - IN S T R . PNL. HARN. TO DIR.&HAZ. WARN. SW. HARN. A S M . - U N D E R IN STR . PNL. AT S T E E R IN G COL. „...
  • Page 795 /’'s r * ----------------- — ------------------------------------- £ > - -------- BAT. B O X HTR. 1 2 W H T - * 4 BAT. BOX -12 GRN — HEATERS ----- ---------------------------------------— ^ — i & w J |^U P P E R ' B L K —...
  • Page 796 C O N TR O L SW. ENG. A LA R M ACCESSORY FEED R E LA Y 'TA C H O G R A P H S LOW C O O LAN T IN D IC A TO R 8 2 SPD.
  • Page 797 POWERED — ( U ------ ------- H CflB W|MD 0W BLU E I V , IT T R B L U E W H T T R WINDOW jDOWN^j — (2]------ -------- A -^ n r v J * |_IFT (R.H.) —...
  • Page 798 LEGEND S Y M B O L J U N C T IO N F U N C T IO N L O C A T IO N ® 3 WAY C O N N . - IN S T R . PN L.'H A R N . TO C O O L A N T L O S S INDIC. H A R N .--------AT C O N T R O L SW. IN C O N S O L E C O M P ’T. 5 P O S T JCT.—...
  • Page 799 ----- -/2 --------- W H T — < W ''W | I BAT. B O X .H T R ~yoj g r n — BAT. BO X H T R S. — 12 REV. C 1 (U P P E R ) -------- 12 B L K O A / W v...
  • Page 800 LO. A IR SW. ■ - 1 6 B L K G R N TR LO. COOLANT LO. C O O L A N T INDICATOR - — 1 0 B R N B L K T R IN D IC A T O R IB R E D W H T T R —...
  • Page 801 C LU TCH SW. 1 8 - (!>• CAB FRT.MKR. LPS I8 G R A Y © —)!' F U E L GA. CANADIAN MIRROR L P S R.H. L.H. I8 G R A Y ----- !:• WATER TEMP GA. i----- 1 r A "...
  • Page 802 GHO-CAB-ALL MODELS DASH 4 ^ 4 GFtO. S T R O P ENGINE GRO.-ENGNE-FRAME MTD. BAT. > t| tra m s . ------------ B l k ---------fra m e RPO. Figure 41—Cab, Engine, and Chassis Wiring—HM, JM-80 Sheet 1 of 6...
  • Page 803 IGNITION CONTROL SWITCH BRAKE WARNING T T R.PO. JL4-VA C. MODELS LOW VAC ALARM BUZZER R.PO. JL 4 -VAC MODELS TEMPERATURE GAUGE Figure 47— Cob, Engine, and Chassis Wiring—HM, JM-80 Sheet 2 of 6...
  • Page 804 I I I )— O -yySiA - FUEL GAUGE G BRN. WHT. CR. TR. f u e l TANK UN 7 FUEL TANK SELECTOR SW- BRN. WHT. Cff. TR.-<Q>.)8 8 RN. WHT. CR. TSC 'J------ >8 T M (HIM) - »...
  • Page 805 CAB FRT. MKR.LPS CAB FRT. MK R.LPS ■-lB B LK -< --y^SLZ 7 1 * \ R.H. ■ - '8 WHT- -c ------- 1 CANADIAN 18 BLK MIRROR LPS 18 BLK — i - - - i R.PO. 0 4 6 - ~ /8 W H T - - c : ^ \ ^ ~ Z .
  • Page 806 2 SPO. W/S WPER a \»SHER BACK-UP LPS. -2 SPEED AXLE ( 1MCN HEATER Figure 41—Cab, Engine, and Chassis Wiring—HM, JM-80 Sheet 5 of 6...
  • Page 807 LEGEND C IR C U IT SYMROI JU N C TIO N FUN C TIO N LOCAT ION ID E N T IF IC A T IO N © - INSTR PANEL HARM. TO W/S WIPER MTR. a WASHER HARN. A S M - ! ■...
  • Page 808 G R O U N D - D A S H GRD.-ENGINE TRANS. l | | ' *0 0 BLK. — j | l FRAME DUAL -I2V. BAT.-FRAME MTD. RPO. T68 ( H J/JJ70 ONLY ) SINGLE-I2V. BAT.-FRAME MTD.- STARTER STARTER INTERLOCK STARTER INTERLOCK HV/JV70 ONLY...
  • Page 809 CONTROL SWITCH t e m p e r a t u r e g a u g e Figure 42—Cab, Engine, and Chassis Wiring—HV, JV-70 Sheet 2 of 6...
  • Page 810 R.H. <w^v- FUEL GAUGE -1 8 BRN. WHT. CR. TR. ■ F U E L G A . TAN K UNIT F U E L TAN K S E L E C T O R SW . f t H t8B m .W H T .C R .
  • Page 811 if f ts a LO W E R B E A M U M T P KG . L P y — PURPLE LIGHTING f g } ----- 16 BLK.---------< Z £ > - / 6 P W G .LP I P P E R L O W E R B E A M UNIT...
  • Page 812 STO P SWITCH EMERGENCY PARK B R A K E STO PLIGHT SWITCH R.PO. J 7 4 T R A IL E R EM ERGENCY STO PLIGHT SWITCH R.PO . J9 I 2 SPD. W/S WIPER a WASHER BACK-UP L P S . 2 S P EEO A X L E <...
  • Page 813 C IR C U IT i d e n t i f i c a t i o n LEGEN D SYMBOL JUNCTION FUNCTION LOCATION 4 WAY M U LTIPLE CONNECTOR -IN S T R . PANEL HARN. TO W/S WIPER MTR. 8 WASHER HARN, ASM .- - A T DASH P A N E L -B E H IN D GLOVE BOX COMP'T.
  • Page 814 Figure 43—Cab, Engine, and Chassis Wiring—TM80 Sheet 1 of 6...
  • Page 815 (1.52 ±07 OHM) - V-6 CYL ENG [1.80+05 OHM)-INLINE CYL ENG [ l.S 5 t0 5 OH M )-V-8 CYL ENG SPARK PLUGS (L.H.S]) HI TENSION Wifi CONTROL SW ITCH E L E C T R IC TACHO. R.RO. U16 DISTRIBUTOR 1 6 5-4-3 2 V-6 CYL.
  • Page 816 ENGINE ALARM BU ZZER- R.PO. X 5 4 Z ^-I4 G R N ~ {U ------------------14 BLK — Qf ]— 14 DK GRN | A X L E S H IF T M TR. E L E C T R IC 2 S P EED - Q --- 14 PINK-CH-14 PlNK- I6 B L K —...
  • Page 817 H EA TER . U63 r a d i o Figure 4 3 — Engine, C a b , a n d C h a s s is W i r i n g — T M 8 0 S h e e t 4 o f 6...
  • Page 818 L IG H T IN G L.H. PARK L P (CHEV. ONLY) 10 R E D _______ -> 8 — < -£ Z;'; tv. CANADIAN M A R K E R L IG H T S MIRROR LPS R.P.O. D 46 \ l .
  • Page 819 C IR C U IT ID E N T IF IC A T IO N LE G E N D S Y M B O L J U N C T IO N F U N C T IO N L O C A T IO N □...
  • Page 820 CAB GROUND • H i' FRAME C A B * lH ENGINE GROUND E N G IN E .|^ i ■ J | l f RAME Figure 44—Cab, Engine, and Chassis Wiring—TV70 Sheet I of 6...
  • Page 821 C O N T R O L S W IT C H O IL P R E S S . GAUGE WATER T EM P GA. F U E L GAUGE LOW A IR ALARM BU Z ZER F ig u r e 4 4 — C a b , E n g in e , a n d C h a s s is W ir in g — T V 7 0 S h e e t 2 o f 6...
  • Page 822 LOW A IR T. T. LOW AIR SW. EN G IN E A LA R M ENGINE ALARM B U Z Z E R - P PO. BU Z ZER - R.PO X 5 4 18 p i n k ---------@ - - IQ B L K Y E L L S TR LOW OIL T.
  • Page 823 H EATER RADIO * R.PO HORN Cob, Engine, and F ig u re 4 4 — C h a s s is W i r i n g — T V 7 0 S h e e t 4 o f 6...
  • Page 824 / S I T G R N ---------- © — 1 8 B L K - 16 LT B R N --------------------------- G D ----- IS LT GRN — i L .H .H E A D L P CD-- LIG H TIN G 16 T A N ---------------------------------- 16 T A N - L.H, PARK L P...
  • Page 825 ■I8D K GRN- < 2 > - i e B L K -------- R .H .S T O P -T A IL )C l c — ^ & D IR . L P I8B R N < 2 y - 16 PURPLE ( = 3 - / S a L K —...
  • Page 827 If condition of se a l is shock loads. Rubber cushions and rebound springs deteriorated, se a ls should be replaced. are subject to deterioration, weakening, andbreak- Figure 1—Radiator Upper Mounting (HM, JM80) CHEVROLET -SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 828 Flgure3—Radiator Installation fAlum. Tilt and a ll Conv. Cab Models, except HM, JMBO) shroud w ill not in terfere with operation of fan. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 829 Speed Nut Flat Washer Control Island Spring Frame Bracket Radiator Core and Support CORE LOWER MOUNTING CORE UPPER MOUNTING T-6846 Figure 5—Radiator Upper and Lower Mounting (Series 70-80 Steel Tilt Cab) (Typical) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 830 9. Carefully r a ise and rem ove radiator with attached chainfall. Installation (Refer to Fig. 3) Using a chainfall and slin g (attached to Figure 6 —Radiator Tie Rod Installation radiator upper mounting brackets) carefully lift CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 831 If it should becom e n ecessa ry to center the L oosely in sta ll se v e r a l bolts and nuts at each side CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 832 (see "Specifications" DO NOT u se glycol ether (methoxy propanal type) at end of th is section ), p ressu re valve opens and base permanent type a n ti-freeze coolants in DH CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 833 Shutter spring action then opens the shutters. SHUTTERS SHUTTER MAINTENANCE Maintain radiator shutter unit in fr e e working CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 834 , m oval of s e a l to prevent damage to lip of vane, and tighten firm ly. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 835 D elrin eye cated by a p ressu re r is e as indicated on p ressu re bushing. gauge. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 836 25 Jam Nut Return Spring 17 Adjusting Nut 26 Piston Follow er 9 Cylinder Head 18 Control Rod A ssem bly T 6 8 4 5 Figure I 0—Shutter Control A ir Cylinder (TV70) CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 837 4. Start veh icle, bring air p ressu re in system le a st 65 p si. Check shutter operation, and system up to norm al (approximately 105-120 p si). Check for leak s. sy stem for air leak s. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 838 9. Use only Ethylene Glycol base coolant m eetingG M Specification I899-M . 10. Drain and flush cooling system every other year, preferably at the begin­ ning or end of winter operation. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 839 F U E L SYSTEM SECTION 5A - HYDRAULIC BRAKES J-8824 Carburetor Float Gauge J-4707 Adjusting Tool J-4395 Float L ever Bending Tool J-22348 Brake Spring Tool ♦L isted in m ore than one section. CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...
  • Page 840 SECTION 6T - AIR COMPRESSORS AND GOVERNORS J-6408 Headlight A im er (Single Lights) *J-23573 B elt Tension Gauge J-6663 Headlight A im er (Dual Lights) ♦ L isted in m ore than one section . CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL...

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