Chevrolet 50 Series 1972 User manual

40-60 SERIES TRUCK

SUPPLEMENT

SERVICE MANUAL

1 9 7 2

CHASSIS SERVICE MANUAL

SECTION INDEX

SECTION

NAME

0

LUBRICATION

SUPPLEMENT

3

FRONT SUSPENSION

c o v e rin g

4

REAR SUSPENSION

SERIES 40-60

CHEVROLET TRUCKS

5

BRAKES

6A

GASOLINE ENGINES

FOREW ORD

6D

ENGINE MOUNTINGS

6K

ENGINE COOLING

SYSTEM

This manual is a supplement to the 1971 Series 40-60

Truck Service Manual. It includes procedures for main

tenance and adjustments, minor service operations, and

removal and installation for components of Chevrolet Series

40 through 60 Trucks. Procedures involving disassembly

and assembly of major components for these vehicles are

contained in the 1972 Chevrolet Passenger Car and Series

10-30 Truck Overhaul Manual or the 1972 Series 40-60

Truck Overhaul Manual Supplement.

This manual should be kept in a handy place for ready

6M

ENGINE FUEL SYSTEM

6T

AIR COMPRESSOR

AND GOVERNOR

6Y

ENGINE ELECTRICAL

reference. If properly used, it will enable the technician to

better serve the owners of Chevrolet built vehicles.

All information, illustrations and specifications con

tained in this literature are based on the latest product

information available at the time of publication approval.

The right is reserved to make changes at any time without

notice.

7

TRANSMISSIONS

AND CLUTCHES

9

STEERING SYSTEM

10

WHEELS & TIRES

11

SHEET METAL

CHEVROLET MOTOR DIVISION

General Motors Corporation

DETROIT, MICHIGAN

12

CHASSIS ELECTRICAL

AND INSTRUMENTS

ALPHABETICAL INDEX

Printed in U.S.A.

Sec. 0

Page 1

SECTION 0

J luh nica tio -n

All information contained in Service Manual ST-331-71 under

LUBRICATION (SEC. 0, Page 1 through 12) will apply to vehicles cov

ered by this publication. The following information will also apply:

TRANSMISSION CAPACITY CHART

Manual Transmission

U.S.

IMP.

SM465

8

6%

NP435

7

5%

NP540 9

U

NP542 10

8%

CL282 12

10

CL285

12

10

CL325

14

11%

CL327

14

11%

SP5652

13

10%

SP5752 15

m

SP5756 15

12%

Automatic Transmission

MT40

18*

15

MT41

18* 15

AT475 10*

8l4

AT540

22*

18%

* Filter Change Only.

Auxiliary Transmission

SP6041

8 6%

SP7041 11

9%

ENGINE OIL

(SYMBOL “E” ON CHARTS)

ENGINE OIL

It is recommended that new engines should

have the first oil change at 3,000 m iles, thereafter

at 3 months or 4,000 mile intervals. This drain

interval may be increased or decreased depending

upon the severity of service and experience with

specific oils or the recommendations and used oil

* analysis as furnished by the supplier. Such a pro

cedure would be helpful in establishing the most

practical oil change period for the particular

service. Refer to Service Manual ST-331-71.

Contaminated engine oil can cause a malfunc

tion of valve lifters or the PCV valve. A sticking

valve lifter can cause leakage of unburned gases

through the valve. A plugged or sticking PCV valve

will affect carburetor mixture and will prevent

proper crankcase ventilation.

ENGINE OIL FILTER

Oil filter should be replaced at the first oil

change and each oil change thereafter to filter

sm all particles which could affect valve lifters or

PCV valve action.

RECOMMENDATIONS

The oil industry markets various types of en

gine oil under certain service designations and

specification numbers.

The selection of a reliable supplier, with close

attention to his oil and filter element change rec

ommendations can provide satisfactory lubrication

and longer life for engine.

Gasoline and D iesel Engines

Use only high quality oils which are intended

for Service Designations "MS” and "DM” (SE/CC

New A.P.I. Designation) see NOTE.

The following additive limitations, which re

quire emphasis, have been placed on the recom 

mended MIL-L-2104B (now superseded by MIL-L-

46152) and Supplement 1 oils:

1. Sufficient zinc dithiophosphate to produce

a minimum of 0.07 and a maximum of 0.10 per

cent by weight.

2. Sulfated ash (ASTM D-874) of 1.00 per cent

maximum by weight, except lubricants that contain

only barium detergent-dispersants where 1.50 per

cent by weight is allowed.

NOTE: Supplement 1 engine oils (based upon

now obsoleted MIL-L-2104A) have been superseded

by MIL-L-2104B engine oils. However, Supplement

1 engine oils MS-DM (SE/CC New A.P.I. D esig

nation), with a history of satisfactory performance

are available, and may be used.

The use of proper engine oils and oil change

intervals are your best assurance of continued re

liability and performance from your engine.

IMPORTANT: Non-detergent and other lower

quality engine oils are specifically not recom 

mended.

POWER STEERING FLUID

(SYMBOL "S32”)

GM Approved Hydraulic Power Steering Fluid

is available through wholesale warehouses and truck

Sec. 0

Page 2

LUBRICATION

centers. Check fluid level every 6,000 m iles or 4

months, whichever occurs first. Fill pump reser

voir to proper level. If GM Power Steering Fluid is

not available, DEXRON® Automatic Transmission

Fluid (Symbol SI9) may be used.

CAUTION: DO NOT use GM Power

Steering Fluid in automatic transmissions.

AUTOMATIC TRANSMISSION FLUID

(SYMBOL “SI 9” ON CHARTS)

(Refer to Service Manual ST-331-71)

Oil level in the automatic transmission must

be checked at each engine oil change. Under normal

driving conditions the transm ission fluid should be

changed every 24,000 m iles. Under unusual condi

tions such as off-road (construction) or constant

stop and go driving (pickup and delivery) fluid

should be changed at 12,000-mile intervals. It is

important that transmission fluid level be main

tained at the full mark and NOT OVERFILLED.

ENGINE AND ACCESSORY

LUBRICATION

The following additional information applies to

Lubrication Chart (fig. 4) on page 7 of ST-331-71

Service Manual.

CARBURETOR AIR CLEANER

ELEMENT

Air cleaner should be inspected and serviced

at intervals specified in Emission Control System

booklet, or more often under severe dust conditions,

also, whenever dirt is visible in element or oil.

POWER STEERING RESERVOIR

Fluid level should be checked every 6,000

m iles and filled with S32 Power Steering Fluid, or

if not available with S19 Automatic Transmission

Fluid.

Sec. 3

Page 3

SECTION 3

S u d s K t & n d A X U l

SECTION 3A

f y n x w U A U < f * u n e + t t

All information and alignment instructions in Service Manual

ST-331-71 "FRONT END ALIGNMENT” (SEC. 3A) are applicable

to models covered by this supplement.

SECTION 3B

A xle .

All front axle information in Service Manual ST-331-71 "FRONT

AXLE” (SEC. 3B) is applicable to models covered by this supplement.

All front axle information for the F-120 axle is also applicable to the

F-110 axle. Illustrations and specifications have been updated.

1 Steering Knuckle

9 Axle Center

Spindle

10 Stop Bolt and Lock

2 Kingpin Bushing

Nut

(Upper)

11 Draw Key

3 Kingpin

12 Thrust Bearing

4 Cap Screw

13 Tie Rod End Assy.

5 Kingpin Bearing Cap

14 Kingpin Bearing Cap

(Upper)

(Lower)

6 Gasket

15 Gasket

7 Lube Fitting

16 Kingpin Bushing

8 Shim (Lower) t-8793

1 Steering Knuckle

Spindle

2 Steering Knuckle

Bushing

3 Kingpin Bushing

(Upper)

4 Kingpin

5 Dust Cap

6 Kingpin Nut

7 Cotter Pin

8 Gasket

9 Lube Fitting

10 Washers or Shims

11 Axle Center

12 Stop Bolt and Lock

Nut

13 Thrust Bearing

14 Tie Rod Assembly

15 Plug Retainer

16 Ejqpansion Plug

17 Kingpin Bushing

(Lower) t-8794

Figure 1 —Steering Knuckle (F070 Axle)

Figure 2 —Steering Knuckle (F090 Axle)

T r o n t axle

Sec. 3

Page 4

___________

T-8795

1 Steering Knuckle

Spindle

2 Steering Knuckle

Bushing

3 Kingpin Bushing

(Upper)

4 Kingpin

5 Cap Screw

6 Dust Cap

7 Kingpin Nut

8 Cotter Pin

9 Gasket

10 Lube Fitting

11 Spacers or Shims

12 Axle Center

13 Stop Bolt & Lock Nut

14 Thrust Bearing

15 Tie Rod End Assy.

16 Plug Retainer

17 Expansion Plug

18 Kingpin Bushing

(Lower)

Figure 3— Steering Knuckle (FI 10 and F I20 Axles)

AXLE SPECIFICATIONS

AXLE MODEL

F050-F055

F070

F090 F110—FI 20

KING PIN

Length

.................

6.3594”

7.8906”

8.750”

Diameter

At Top

...............

1.1090”— 1.1094”

1.2492”— 1.2496” 1.1855”— 1.1865” 1.1855”— 1.1865”

At Bottom

...........

1.1090”— 1.1094”

1.2492”— 1.2496”

1.14330”— 1.14340”

1.4330”— 1.4340”

KING PIN BUSHING

Length

.................

— —

1.9063” 1.9063”

Diameter

Outer

................

—

1.4330”— 1.4340” 1.4330”— 1.4340”

Inn er

.................

—

1.1870”— 1.1880” 1.1870”— 1.1880”

STEERING KNUCKLE BUSHING*

Length

.................

Upper

................

1.3438” 1.875”

1.709”— 1.729” 1.760”

Lower

................

1.3438”

1.875”

1.990”— 2.010”

2.150”

I.D. When Installed ....

1.1094”— 1.1124”

1.2496”— 1.2526”

*1.4365”— 1.4375”

1.434”— 1.437”

STEERING KNUCKLE TO AXLE

CENTER CLEARANCE

0.005”

.004”— .012”

.114”— .116” White

SPACING WASHERS AVAILABLE

—

.121”— .123” Yellow .121”— .123” Yellow

.128”— .130” Blue .128”— .130” Blue

SPACING SHIMS AVAILABLE..

0.005”

_

0.010”

TORQUE SPECIFICATIONS

King Pin Nut

...........

_

250 Ft. Lbs. then

Advance to Next

Cotter Pin Hole.

King Pin Bearing Cap, Cap

Screw

................

4 -5 Ft. Lbs. 5 -6 Ft. Lbs.

3 - 5 Ft. Lbs. 3 - 5 Ft. Lbs.

* Ream after Installation

SECTION 3C

f y n & n t S f J S U w a A .

All information on Front Springs contained in Service Manual

ST-331-71 “ FRONT SPRINGS" (SEC. 3C) is applicable to models

covered by this supplement. The following “ Torque Specifications”

chart has been updated.

TORQUE SPECIFICATIONS

C-M-S

Models

(Ft.-Lbs.)

T

Models

(Ft.-Lbs.)

Spring U-Bolt (N u t).................................................

. . 105 - 130 190 - 210

Spring U-Bolt (N u t)................................................. . . *175 - 250

-

Spring Hanger to Frame Bolt (N ut)

..................

60-85

35 - 45

Spring Bumper to Frame Bolt (Nut)

...............

14-22 35 - 45

Spring Bumper to Frame Bolt (Nut)

...............

** 2 - 3

-

Spring Front Eye Bolt (N u t)

..............................

. . 190 - 210 150 - 200

Spring Rear Rebound Pin Retainer (Bolt) . . .

20 - 25

Spring Rear Rebound Bolt (N u t)

........................

75-95

-

Shock Absorber Bracket to Frame Bolt (Nut)

. . 40-50

65 - 95

Shock Absorber Upper and Lower Eye Bolt (Nut) 65 - 95

40 - 50

Shock Absorber Stud to Frame (N ut)................

130 - 190

-

* 9,000 and 11,000 lb. Axles Only.

** 366 and 427 V8 Gas Engines.

SECTION 3D

c J lu b i a n d Q e a s U n G A .

All information in Service Manual ST-331-71 “ FRONT HUBS AND

BEARINGS” (SEC. 3D) is applicable to models covered by this supple

ment. The following revision will also apply:

CLEANING, INSPECTION, AND REPAIR

REPAIR

Brake Drum Replacement

1. Demountable Type. The demountable type drum may be separ

ated from the hub and removed from the vehicle without disturbing the

hub. The drum is held to the hub by the wheel studs and nuts as shown

in figure 4.

Sec. 3

Page 6

FRONT HUBS AND BEARINGS

T-91 15

Side Ring

Lock Ring

Wheel

Wheel Stud Nut

Wheel Stud

Brake Drum

Hub

Cap Screw & Washer

Bearing Cone and

Roller Assy. (Outer)

Bearing Retainer

Adjusting Nut Washer

Adjusting Nut

Hub Cap

Cotter Pin

Backing Plate

Inner Oil Seal

Bearing Cone and

Roller Assy. (Inner)

Spindle

10

11

12

13

14

15

16

17

18

1

2

3

4

5

6

7

8

9

Figure 4 — Front Hub and Bearing with Demountable Wheel and Drum

Sec. 4

Page 7

SECTION 4

( le a / i S u A s n e t t & io s t

All information contained in Service Manual ST-331-71 is ap

plicable to models covered in this supplement. The following informa

tion will also apply:

SECTION 4A

(lean. A xleA. a n d G ottis ioh

IMPORTANT

When parking vehicle equipped with a two- or three-speed axle, the

axle should be shifted into LOW range with engine running. Engage

clutch and transmission to be sure axle has completed shift into LOW

range. Apply parking brake, place transm ission in neutral and shut off

engine. When leaving the vehicle parked or unattended the previous in

structions must be followed:

VACUUM SHIFT SYSTEM

MAINTENANCE

AIR CLEANER

Air cleaner removes dirt particles from at

mosphere which passes into the control valve and

other units. Air cleaner should be removed and

cleaned at regular intervals.

SERVICING AIR CLEANERS

(Refer to Figure 1)

The air cleaner used on Conventional and S50

Models is the metal cup type which uses a hog's

hair type element. This cup is a friction fit on the

air intake pipe and can be removed by pulling

straight off. It can be cleaned by rinsing in a suit

able solvent and reused. Refer to LUBRICATION

(SEC. 0) in this supplement for service intervals.

If cleaner has become so laden with an accumula

tion of dirt, that satisfactory cleaning cannot be

done, replace with a new cleaner.

The air cleaner used on all Tilt-Cab Models

is a plastic encased, synthetic element type filter,

and cleaning is NOT recommended. When cleaner

becomes so laden with dirt, that tapping it against

som e solid surface (such as a work bench) will

not remove foreign matter, then a new cleaner

should be installed.

IMPORTANT: DO NOT OPERATE VEHICLE

WITH AIR CLEANER DISCONNECTED OR RE

MOVED. Figure 1—Air Cleaners

T-9142

HAIR TYPE ELEMENT

PLASTIC HOUSING

SYNTHETIC ELEMENT

)

Sec. 4

Page 8

SECTION 4B

(leal BpAitUfi and Suifiesutiott

HENDRICKSON TANDEM REAR SUSPENSION

Refer to Service Manual ST-331-71 "REAR SPRINGS AND SUS

PENSION” (SEC. 4B), pages 4B-7 and 4B-8 for figures 9, 11 and 12.

EQUALIZING BEAM REMOVAL

AND REPAIR

The following procedures cover removal and

installation of either equalizing beam without re

moving any other units of the suspension system .

When removing an axle assembly, accomplish only

steps required to loosen axle at each end of beam.

EQUALIZING BEAM REMOVAL (Fig. 9)

1. Raise and support frame to remove weight

from beams.

2. At axle brackets, remove nuts (5), washers

(7), and bolt (1). Pry adapters (2) from bushings

and brackets.

3. With blocking under beam cross tube (fig.

1) to support weight of beams, remove saddle caps

attached with four nuts and flat washers.

4. Lower the cross tube and beams, then slide

beams from tube ends.

EQUALIZING BEAM INSPECTION

1. Inspect beam end bushings and beam center

bushing for evidence of damage or deterioration of

the rubber. If any damage is evident, replace bush

ings as directed under "Equalizing Beam Bushing

Replacement" later in this section.

2. Inspect cross tube and thrust washers and

replace if bent or worn.

EQUALIZING BEAM BUSHING

REPLACEMENT

Press old bushing out, using a suitable driver

or press to exert force on bushing outer sleeve.

Press new bushing into place, exerting force on

bushing outer sleeve until outer sleeve extends an

equal distance through beam at both sides.

EQUALIZING BEAM INSTALLATION

(Refer to Fig. 9)

1. Position beams, with cross tube and thrust

washers in place at spring saddles and axle brackets.

NOTE: At axle end of beam, install adapters

(2, fig. 9) at each side of bracket and into bushing.

IMPORTANT; The cut-off (flat) side of each

adapter must be located in a vertical position as

shown in figure 11.

2. Install bolt and washer through adapter and

axle bracket at each end of equalizing beam (fig. 11).

NOTE: Install bolt and washer from inner side

with nut located toward wheels (fig. 11). Tighten

nuts or bolts to torque listed in "Specifications" at

end of this section. Figure 12 shows section through

mounting.

3. Install spring saddle caps to attach beam

center bushing to spring saddle. Install saddle cap

stud nuts or cap screws and tighten to torque listed

in "Specifications" at end of this section.

1

Beam Center Bushing

7

Setscrew

2 Spring Saddle 8

Equalizing Beam

3 Spring Assembly

9

Cross Tube

4 Spring Saddle Top Pad

10

Spring Saddle Cap

5 Top Pad to Spring

11 Stud

Saddle Bolts

12

Thrust Washer

6

Lock Nut

13

Bushing

Figure 1— Section Through Spring Saddle and Beam

Sec. 5

Page 9

SECTION 5

lin & k e A ,

All information in this section in Service Manual ST-331-71 also

applies to vehicles covered by this supplement, except as specifically

stated in the following procedures:

SECTION 5A

< M - t^ d n < u c U c B ' l a h e i .

BRAKE SYSTEM MAINTENANCE

CHECKING FLUID LEVEL

A sticker (fig. 1) reading "CHECK BRAKE

FLUID LEVEL EVERY 30 DAYS OR 3000 MILES”

is affixed to the cover of each brake master cyl

inder. Figure 2 illustrates a typical cover with the

sticker applied.

Fluid level should be maintained to within V2"

of top of master cylinder reservoir.

VACUUM GAUGE

Two vacuum gauges are used oft some ve

hicles. Two gauges are standard equipment on all

■

school buses (dual-split-brake system) and optional

on all other vehicles equipped with dual (split)

brake system s. These gauges are mounted on a

special bracket below the center of the dash panel.

One gauge is connected to one vacuum system

of the dual brake system and the other gauge is

connected to the other vacuum system . Vacuum

gauge readings may differ during operation of the

vehicle. However, if the readings differ by ten

inches of mercury or more for an extended period

of vehicle operation the vacuum system s should be

checked immediately to determine causes. If the

vacuum gauge is suspected of being faulty, check

gauge according to instructions in Service Manual

ST-331-71, page 5A-22. Otherwise, check vacuum

system components for leaks or malfunctions.

Figure 1—Brake Fluid Sticker

Figure 2—Master Cylinder Cover

)

Sec. 5

Page 10

SECTION 5B

A i / i B 'l a k e i

BREATHER AND FILTER

ASSEMBLIES

Figures 1 and 2 illustrate three different

breather and filter assem blies. Figure 1 (left view)

shows the original type breather. Replacement is

covered in Service Manual ST -331-71, page 5D-89.

To remove the intermediate type filter (fig. 1,

right view) or the latest type (fig. 2), remove two

screw s and lift cover and filter off housing. To

install, set filter in place on housing and attach

cover. Filters can be cleaned and reused but

breather cannot. If removed, breather must be

replaced with new parts.

AIR LINE TORQUE

Refer to page 5B-53 of Service Manual ST-

331-71 and change the following torque values:

3/8-inch from 30-50 to 50-75

}£-inch from 90-115 to 120-150

5/8-inch from 100-125 to 150-200

Also change the statement "retorque to higher

than minimum value" to read: "Retorque to higher

value."

Figure 2— Filter Installed

i

Sec. 6A

Page 11

SECTION 6A

Q a d - a lln e . C n c u n e A ,

The information pertinent to truck models covered by this Supple

ment is the same as given in Service Manual ST-331-71 (pages 6A-1

thru 6A-34) with the following exceptions and/or additions:

ENGINE MAINTENANCE

Inspection, adjustment or replacement of em is

sion control related components must be performed

on a time or mileage basis as indicated. Good

judgment is required in replacement of parts in

those cases where the accumulated mileage is

substantially lower during the specified time period.

SERVICING AIR CLEANER

Air cleaners should be inspected and serviced

every 12,000 miles or more often under severe

dust conditions; also, whenever dirt is visible in

element or oil. Refer to "AIR CLEANERS” (SEC.

6M) of this supplement or ST-331-71 Service

Manual.

IMPORTANT: Vehicle operation under condi

tions such as heavy dust, continuous short trips,

stop and go driving, etc., is not considered normal

use and therefore more frequent maintenance will

be required. Such additional maintenance require

ments are included below where applicable.

Thermostatically Controlled Air Cleaner

The air cleaner should be inspected to make

certain that all hoses and ducts are intact and cor

rectly installed. Operational function should be

checked by inspecting position of valve in air intake.

With engine stopped, valve should be open. At

underhood temperature below 100°F., with engine

running, valve should be partially or fully closed.

As engine underhood temperature rises, the valve

should open.

CHECKING DRIVE BELTS

Fan belt tension on vehicles equipped with

V-belts should be adjusted to 120 - 130 pounds on

new belts using BT-33-73F Belt Tension Gauge.

Used drive V-belts should be adjusted to 80 - 90

pounds. Gauge should be placed at center of the

greatest span.

IMPORTANT: After a belt has been in oper

ation one hour or approximately 50 m iles, it is

considered used. Belt dressing can be used to ex

tend belt life. When V-belts are worn they should

be replaced, as excessive tightening will not pre

vent slippage and can cause damage to bearings.

SPARK PLUGS

Replace spark plugs at 12,000 mile intervals.

Use of leaded fuels results in lead deposits on

spark plugs and can cause misfiring at m ileages

less than 12,000 m iles. Where m isfiring occurs

prior to 12,000 m iles, spark plugs in good condition

can often be cleaned, tested and reinstalled in an

engine with acceptable results.

ENGINE COMPRESSION

Minimum compression recorded in any one

cylinder should not be less than 70% of highest

cylinder. For example, if the highest pressure in

any one cylinder is 150 lbs., the lowest allowable

pressure for any other cylinder would be 105 lbs.

(150 x 70% = 105).

This test should be performed to provide rea

sonable assurance that engine condition is suffic

iently efficient to prevent leakage of unburned

gases. If a problem exists, have corrections made.

DISTRIBUTOR POINTS, CAM LUBRICATOR

Distributor points should be inspected prior to

performance of tune-up adjustments. Burned or

pitted points must be replaced. Points in good con

dition may be reused after readjustment and the

installation of a new cam lubricator. New points

and cam lubricator should be installed at least

every 24,000 miles.

DISTRIBUTOR CAP

The interior and exterior of the distributor

cap should be carefully inspected and cleaned to

prevent misfiring and deterioration.

SPARK PLUG WIRES

Inspect spark plug wires for evidence of check

ing or cracking of exterior insulation and a tight

fit in the distributor cap and at the spark plugs.

Exterior of wires should be cleaned, any evidence

of corrosion on ends removed and wire replaced

if deteriorated.

TIMING, POINTS (DWELL), IDLE SPEED

These adjustments must be performed accur

ately, following the specifications shown on the

label under the hood. Adjustments must be made

with test equipment known to be accurate.

Sec. 6A

Page 12

GASOLINE ENGINES

Figure 1 — Flywheel Housing and Adaptor Plate

(350 and 366 V8 Engine)

Proper functioning of the carburetor is par

ticularly essential to control of em issions. Correct

mixtures for em ission compliance and idle quality

have been preset. Plastic idle mixture limiters have

been installed on the idle mixture screws to pre

clude unauthorized adjustment. These idle limiters

are not to be removed unless made necessary by

some major carburetor repair or replacement which

affects the idle screw adjustment.

POSITIVE CRANKCASE VENTILATION VALVE

Replace the PCV valve at 24 months or 24,000

mile intervals (whichever occurs first). PCV valve

hose, when removed for valve replacement, should

be blown out with an air hose to make certain that

it is clean. The PCV valve should be replaced at

12 months or 12,000 miles (whichever occurs first)

when the vehicle is used under the following con-

ditionsi

• Driving in dusty conditions.

• Extensive idling.

• Short trip operation at freezing temper

atures (engine not thoroughly warmed up).

POSITIVE CRANKCASE VENTILATION

SYSTEM - HOSES AND CONNECTIONS

The PCV system should be checked for satis

factory operation at 12-month or 12,000-mile in

tervals using a tester such as the AC Tester CT-3.

POSITIVE CRANKCASE VENTILATION

BREATHER OR FLAME ARRESTER

The breather or flame arrester should be re

moved and cleaned at 12,000 mile intervals. Im

merse in cleaning solvent to remove all deposits

and allow to drain before reinstalling.

MECHANICAL VALVE LIFTERS

Intake and exhaust valves on V6 engines should

be adjusted at 12,000 mile intervals.

MANIFOLD HEAT VALVE

In-Line engines and some V6 and V8 engines

are equipped with a manifold heat valve which should

be checked for free operation. A binding valve may

be freed up with General Motors manifold heat

valve lubricant or equivalent. (NEVER USE ANY

OTHER TYPE LUBRICANT.)

FLYWHEEL HOUSING ADAPTER

PLATE

Figure 1 shows the flywheel housing adapter

plate used with 13-inch clutch on 350 and 366 V8

engines.

Inspect engine front and rear mountings as

part of regular engine maintenance program. Be

sure all bracket attaching bolts are kept tight.

Refer to ENGINE MOUNTINGS (SEC. 6D) for engine

mounting information.

UNDERPAN

FLYWHEEL HOUSING

ADAPTER

EXTENSION COVER

T-9141

Sec. 6A

Page 13

GASOLINE ENGINES

TUNE-UP CHART

(IN-LINE ENGINE)

Except as otherwise indicated, the following specifications apply to both engine models.

......................................................

.............15-3-6-2-4

ENGINE TYPE AND NUMBER OF CYLINDERS

..............................

In-Line,

6

-Cyl.

COMPRESSION RATIO

250 Engine ................................................................................ 8.5:1

292 E n g in e ................................................................................ 8.0:1

CYLINDER COMPRESSION (PSI)

At Cranking S p ee d ........................................................................ 130

Max. Variation Between Cylinders

......................................................

20

SPARK PLUG MAKE AND NUMBER

250 Engine .......................................................................... A.C.-R46T

292 Engine .......................................................................... A.C.-R44T

Spark Plug Gap (A ll)..................................................................0.035"

Plug Tightening Torque (Ft.-Lb s.)............................................. 13-17

IGNITION DISTRIBUTOR

Dwell Angle (D egrees).................................................................. 31-34

Point Gap (N ew )........................................................................ 0.019”

Point Gap (U sed )

...................................................................... 0.016”

Contact Lever Spring Tension (O z.)................................................ 19-23

IGNITION TIM IN G

..............................

Refer to Ign. System Specs. (Sec.

6

Y)

VALVE LA S H .................................................................................. Zero

NOTE: Valve lifters are hydraulic type. Refer to “Cylinder Head Bolt

Torque and Rocker Arm Adjustment” in this section for instructions.

ENGINE GOVERNOR SETTING . . . .Refer to Governor Charts at end of Gasoline

Engine Fuel Systems (Sec.

6

M) in this manual.

ENGINE IDLE SP EE D

................

Refer to appropriate chart in "Gasoline Engine

Fuel Systems” (Sec.

6

M) in this manual.

FUEL PUMP PRESSURE (P S I)............................................................... 4-5

CYLINDER HEAD BOLT TORQUE (FT.-LBS.)

........................................

90-100

TORQUE WRENCH SPECIFICATIONS

(IN-LINE ENGINES)

Torque wrench specifications listed below apply to clean dry threads except as otherwise indicated.

ITEM FT.-LBS. ITEM FT.-LBS.

Push Rod Cover B o lts

...................................................................... 6-8 Main Bearing Cap B o lts ................................................................. 60-70

Cylinder Head B o lts..................................................................... 90-100 Oil Pump B o lts................................................................................9-10

Manifold Clamps (O uter)................................................................ 15-20 Oil Filter (Throw-Away T yp e)................................. (Filter Gasket Oiled 20-25)

Manifold Clamps (Except O uter)...................................................... 25-30 Oil Filter Stud (If U sed)...................................................................45-50

Exhaust-to-lntake Manifold B o lt s..................................................... 25-30 Crankshaft Damper B o lt ................................................................. 40-60

Thermostat Housing B o lts.............................................................. 25-30 Flywheel Bolts

Water Outlet Housing B o lts ........................................................... 15-20 250 Engines............................................................................. 55-70

Water Pump B o lts ........................................................................ 13-17 292 Engines ..................................................................

1 05 41 5

Engine Front Cover B o lts ..................................................................5-7 Flywheel Housing B o lts................................................................... 25-30

Spark Plugs— 5 /8 ” Wrench Size— Tapered Seat P lu g

...................

13-17 O ilPan Bolts

End B o lts .................................................................................. 8-12

Connecting Rod Bolt Nuts ^ xc- ..........................................................................

®-8

250 En gin es............................................................................. 30-35 Oil Pan Drain Plug B o lts ...........................................................1/2 15-20

292 En gin es............................................................................. 35-45 7 /8 20-25

Sec. 6A

Page 14

GASOLINE ENGINES

TUNE-UP CHART

(V6 ENGINE)

TYPE AND NUMBER OF CYLINDERS...................................60°, V-6 FIRING ORDER 1-6-5-4-3-2

COMPRESSION RATIO IGNITION TIM ING Refer to Ign. System Specs. (Sec. 6Y)

351C Engines ........................................................7:1 VALVE LASH

CYLINDER COMPRESSION (PSD Intake 0.012”

At Cranking Speed................................................... 125 Exhaust 0.018

Max. Variation Between Cyl.............................................30 ENGINE GOVERNOR SETTING (No Load RPM)** If Used

SPARK PLUGS* 351C 3900

M ake................................................................. AC

IDLE SPEED

............................. Refer to appropriate chart in

Type and Gap "Gasoline Engine Fuel Systems" (Sec. 6M) in this manual.

35 1C .................................................. CR 43 N, 0.035”

Tightening Torque (Ft.-Lbs.)..........................................32 FUEL PUMP PRESSURE ................................................ 5-6V2

IGNITION DISTRIBUTOR CYLINDER HEAD BOLT TORQUE (FT.-LBS.)

...............................

60-65

Dwell Angle (Degrees)............................................. .31-34 *|n extremely cold regions use plugs with higher heat range.

Point Gap (New) .................................................. 0.019”

Point Gap (Used)..................................................0.016” **With engine broken in. Full load setting is approximately 300 RPM

Contact Lever Spring Tension (Oz.)

.................................

19-23 less than No Load RPM, and will vary from engine to engine.

TORQUE WRENCH SPECIFICATIONS

(V6 ENGINE)

Torque wrench specifications listed below apply to clean dry threads except as otherwise indicated.

ITEM

Rocker Arm Adjusting Screw

Rocker Arm Shaft Bracket Bolts

Rocker Arm Shaft Cover Bolts

Valve Lifter Cover Bolts

.....

Distributor Clamp B o lt

.......

Cylinder Head Bolts

..........

Intake Manifold Bolts

........

Exhaust Manifold Bo lts

........

Water Outlet Manifold B olts....

Thermostat Housing Bolts ....

Front Cover Bolts

...........

Connecting Rod N u ts

........

Main Bearing Cap Bolts

Main Bearing Cap Bolts (Except W Rear)

...................... 130-140*

Rear

[Vi"

Bolts) ............................................... 90-100*

ITEM FT.-LBS.

Oil Pump Cover Screws ............................................. 10-15

Oil Pump to Block Bolt

.

............................................... 30-35

Oil Filter By-Pass Valve Plug (When Used)............................. 35-40

Fuel Pump Eccentric B o lt........................................... 55-65*

Oil Filter Housing to Cylinder Block Bolts ........................... 26-36

Oil Filter Center Stud (When Used).................................... 45-50

Oil Filter Assy (Filter Gasket Oiled).................................... 20-25

Spark Plugs ......................................................... 30-34

Flywheel Housing Bolts

...............................................

50-60

Flywheel to Crankshaft B o lts

......................................

100-110

Hub-to-Crankshaft Bolt (Without Cone)

............................. 180-200

Damper or Hub-to-Crankshaft Bolt (With Cone)

.......................

240-260

Oil Pan B olts......................................................... 10-15

Oil Pan Drain Plug .................................................. 20-30

*Oiled with S.A.E. No. 10 Engine Oil. (See Text)

FT.-LBS.

.7-17

20-25

3-5

4-5

12-17

60-65*

25-30

15-20

20-25

22-27

55-65*

Sec. 6A

Page 15

GASOLINE ENGINES

TUNE-UP CHART

(V8 ENGINE)

Except as otherwise indicated, the following specifications apply to all V

-8

Point Opening

engines. New .................................................................................. 0.019”

ENGINE M ODELS

........

- ........................................................350,366, 427 Contact Lever Spring Tension (O z .)

...............................................

19-23

NUMBER OF CYLINDERS AND ENG. T Y P E ..................................

8

Cyl., V Type p|R|NG 0RD[R 1-84-3-6-5-7-2

COMPRESSION RATIO ........................................................................ 8:1

...........................

Refer to Ign. System Specs. (Sec.

6

Y)

CYLINDER COMPRESSION (PSD

At Cranking S p ee d ........................................................................ 150 VALVE LASH ................................................................................. ero

Max. Variation Between Cylinders ............................................. 20 Note: Valve Lifters are hydraulic type. Refer to “Cylinder Head Bolt

SPARK PLUG MAKE S NUMBER ' X i o n s Rocker A™ AdiuStment" ™ thiS f0'

427 ..................................................................................... AC-R42T

350 ..................................................................................... AC-R44T ENGINE IDLE SPEED

..................................

Refer to appropriate chart in

366 ..................................................................................... AC-R43T “Gasoline Engine Fuel Systems” (Sec.

6

M) in this manual.

£ plug list e n in g Torque

(Ft.

-Lbs

.). . . . . . . . . . .

^13-17 « - PUMP PRESSURE (PSD

........................................................ 7 W

CYLINDER HEAD BOLT TORQUE (FT.-LBS.)

350 Eng.................................................................................... 60-70

Dwell Angle (Degrees) .............................................................. 28-32 366 & 427 ............................................................................... 75-85

TORQUE WRENCH SPECIFICATIONS

(V8 ENGINE)

ITEM FT.-LBS. ITEM FT.-LBS.

Rocker Arm Cover B o lt....................................................................3-5 Camshaft Sprocket 15-20

Rocker Arm Stud (366 and 427 Only) ............................................ 45-55 Connecting Rod Caps

Distribute, Clamp Boit..............................................................................20-25 ; ; ;;;;;;;;;;;;;;;;;;;

W * 'H e a d Bolt c„ , „ Main Bearing Caps (350 Engine)

350 ....................................................................................... 60-70 . D .. 7 n on

366 and 427 Engines............................................................... 75-85 tolfe g ! ^ & 4 Only). .V .V .'.'.'.'.V .. . . . V.'.V. .V .V . '.! ! !! ! !! :60-70

Crankshaft Damper B o lt............................................................... 80-90 ^ ^ Caps ^ s 4?/ Eng|„es)

Manifold Bolts (In let)................................................................... 25-35 |nner

^

100-110

Manifold Bolts (Exhaust) ^uter B o lts 100110

350 Engine ................................................................ 18-22 Oil Pump B o lts 60-70

366 & 427 Engine................................................................... 20-30 Qjl pan

Flywheel Housing and Adapter Bolt (When U sed).............................. 25-35

350

Engines 1/4” B o lts 6-7

5/16” B olts

..............

.’

............................................................ 12-15

366 and 427 Engines (1/4” Bolts)................................................. 4-5

Flywheel Bolts

350 Engine............................................................................. 55-65

366 & 427 Engines.................................................................. 60-70 Oil Filter (Filter Gasket Oiled)......................................................... 20-25

Spark Plug 5/8 ” Wrench Size— Tapered S ea t........................... 13-17

oil

Pan Drain P lu g ....................................................................... 15-20

Water Pum p............................................................................... 25-35 Flywheel Housing Underpan........................................................ 6-7 1/2

Sec. 6D

Page 16

SECTION 6D

C ' t u j i n e M a u + U i + u j A .

All information in ENGINE MOUNTINGS (SEC. 6D) of Service

Manual ST-331-71, pages 6D-1 through 6D-3 applies to vehicles cov

ered by this supplement with the following exceptions or additions:

ENGINE CUSHION BOLT AND NUT TORQUE

Bolt to Alum. Bolt to Casting or Nut

Nut Torque

Size

Torque (Ft.Lbs.) Torque (Ft.-Lbs.) (Ft.-Lbs.)

3/8 ” 16-24

12 - 16

25 - 30

15 - 20

7/16" 14-20 20 - 25

40 - 50 25 - 30

1/2" 13-20 30 - 35

55 - 65

40 - 50

9/16" 12-18

40 - 50 60 - 70 50 - 60

5/8" 11-18

50 - 60 130 - 140 70 - 80

3/4" 10-16

90 - 110 180 - 200 110 - 130 T-9146

MOUNTING BOLTS, BRACKET BOLTS, AND NUT TORQUES

BOLT OR NUT SIZE

1/4" - 20-28 8-10

5/16" -

18-24

20-25

3/8" -

16-24

25-30

7/16" -

14-20

40-50

1/2" -

13-16

55-65

9/16" -

12-18

60-70

5/8" -

11-18

130-140

3/4" -

10-16

180-200

7/8" -

9-14

240-270

1"

8-14

325-380

GM 280-M BOLT

FT.-LBS.

e

BOLT HEAD

IDENTIFICATION

GM 300-M BOLT

FT.-LBS.

10-15

25-30

35-45

70-80

85-105

90-110

170-180

300-320

400-430

700-730

BOLT HEAD

IDENTIFICATION

NUT TORQUE

FT.-LBS.

5-8

8-12

15-20

25-30

40-50

50-60

70-80

110-130

210-230

320-350

* 40 - 50

** 55 - 65

*** 60 - 70

Torque for aluminum casting.

ENGINE FRONT MOUNT WITH AT475

TRANSMISSION (ALL ENGINES)

Figure 1 shows left side front mount used on

In-line 6-cylinder Gas Engine and is typical for V6

and V8 Gas Engines. Refer to page 2 for figure 1.

T-9148

to remove brackets, mounts, spacer, bolts, nuts,

and washers.

NOTE: It will be necessary to bend lock tab

before removing the cushion mount bolt (fig. 1) and

after bolt torque. See next page for figure 1.

Replacement

1. Loosen attaching bolts. Raise engine enough

2. Reverse the procedure to install making sure

to torque bolts or nuts as shown on preceding charts.

Sec. 6D

Page 17

ENGINE MOUNTINGS

WASHER

•BOLT

NUT

WASHER

LOCK

‘> " V

FRONT \ V

BOLT

WASHER NUT

M OU NTING

Figure 1—Engine Front Mount with AT475

Transmission (Typical)

SECTION 6K

S 't K f i n e G o a U r u j , S y d t e m

Information pertinent to truck models covered by this supplement

is the same as explained in Service Manual ST-331-71 ENGINE COOL

ING SYSTEM (SEC. 6K), pages 6K-1 through 6K-9, except as indicated

by the following information which is either new or supplemental in

nature.

Reference should be made to RADIATOR AND SURGE TANK

(SEC. 13) in this supplement for information regarding radiator mount

ing, radiator core and surge tank and cooling system filler cap.

COOLING SYSTEM GENERAL MAINTENANCE

TEST COOLANT LEVEL

Engine coolant should be checked for proper

level regularly (daily if necessary, depending on

severity of service) and every six months for cor

rosion and freeze protection to at least -20 F., or

to the lowest temperature expected during the period

of vehicle operation. Each two years or 24,000

m iles, whichever first occurs, cooling system must

be drained, flushed, and refilled with a new coolant

solution.

RADIATOR CORE EXTERIOR

For proper cooling efficiency, the exterior of

the radiator core and A/C condenser, if so equip

ped, must be kept clean. Light brushing and re

verse air flow is usually a satisfactory cleaning

method. Insects can usually be removed with a

garden hose using light water pressure.

COOLING SYSTEM PRESSURE CHECK

Several types of cooling system pressure

checking devices are available locally and manu

facturer's instructions should be followed for

proper use. A typical tester is illustrated in figure

1 and procedures are given below for testing the

pressure cap and cooling system.

1. Testing Radiator Cap

CAUTION: The radiator cap should

not be removed while the engine is at

normal operating temperature. If it is

necessary to remove the cap while the

engine is hot, first relieve the pressure

in the system by turning the radiator cap

counterclockwise to first stop, using cau

tion not to scald hands. Push down on cap

and turn counterclockwise to remove cap.

a. With radiator filler cap removed, wet the

cap gasket with water and wash off any sediment

from sealing surface, then install cap on tester.

b. Pump up pressure by operating pump plung

er handle. When the pressure stamped on cap is

reached, observe tester dial and note the rate of

decrease in pressure.

c. The indicator hand on gauge dial should re

main within the corresponding pressure segment

of scale for approximately 10 seconds. If pressure

cap does not meet this requirement,it should be

replaced with new cap.

2. Testing Cooling System

a. Tighten all radiator andheater hose clamps.

Also, check other connections for leaks at air com

pressor coolant lines, etc.

GAUGE HOSE AND.TAP

PUMP AND GAUGE

ASSEMBLY

FILLER NECK1

SON RADIATOR

OVERFLOW HOSE

Figure 1 — Use of Cooling System Tester (Typical)

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