check oil CHEVROLET CAMARO 1967 1.G Chassis Owner's Guide

REAR SUSPENSION AND DRIVE LINE 4-15

ship of parts, then install Spacer J-
7574-
3 over

the partially installed bushing and between the

sides of the control arm.

f. Continue to tighten J-
21058-
8
until bushing is

pulled flush against control arm. Do not exert

undue force against control arm after bushing is

installed. Overtightening of J-21058-
8
will cause

damage to walls of control arm.

g. Disassemble tools and inspect bushing for proper

installation.

Replace the rear bushing as follows:

a. Position Puller Screw J-21058-8 through Re-

mover Adapter J-21830-2 so that head of screw

is opposite button end of remover. Install this

assembly, threaded end of sc'rew first, through

bushing to be removed.

b.
Install Receiver J-21830-4 and Bridge J-21830-7

. over screw and against control arm. Position

thrust bearing against J-21830-7 and screw

J-21058-8 snugly against bearing. Install Spacer

J-
2183d-
3
between sides of control arm and over

bushing.

c. Check tool installation for proper alignment and

tighten J-21058-8 to withdraw bushing from con-

trol arm. Refer to Figure 35 for installed view

of tools.

d. Disassemble tools and position Installer Adapter

J-21830-2 on flanged end of new bushing. Posi-

tion bushing in control arm making sure of cor-

rect installation. Small end of bushing will pass

through one side of arm without any interference.

e. Install J-21830-4, J-21830-7, thrust bearing and

J-21058-8 on threaded end of J-21058-15 as

shown in Figure 36. Tighten J-21058 to main-

tain proper relationship of parts; then position

Spacer J- 21830- 3 over bushing and between sides

of control arm.

f. Tighten J-21058-8 until bushing is fully seated
J-21058-8 J-21830-7 J-21830-4 J-21830-3 J-21830-2

\

J-2K

X
D58-8
J-218
30-7

IP

•he?

21830-4
J-21830-2

JfSir

J-21830-3

Fig.
35—Lower Control Arm Rear Bushing Removal

(Chevrolet)
Fig.
36—Lower Control Arm Rear Bushing Installation

(Chevrolet)

against side of control arm. Do not apply undue

pressure to J-21058 after bushing is seated--to

do so may cause permanent distortion to control

arm.

g. Disassemble tools and check bushing for proper

installation.

Installation

NOTE:
Make sure control arm is reinstalled

in proper forward attaching position. Reinstall

in same hole as noted during removal. Top

attaching hole is used for all installations except

station wagons and heavy-duty suspension (RPO

F41).
Opposite arm must be installed in cor-

responding position.

1.
Position the control arm between the mounting

brackets and loosely install the pivot bolt retaining

nuts in the proper position.

2.
Install spring and shock absorber as outlined in this

section.

3.
Lower vehicle so that weight is placed on sus-

pension components and torque all affected parts to

specifications.

Chevelle Upper and Lower

Removal

NOTE:
If both upper control arms and both

lower control arms are to be removed at the

same time, remove both coil springs as outlined

under "Coil Spring Removal".

1.
Raise vehicle to a height that will allow axle assem-

bly to hand freely and position supports under both

frame side rails.

2.
Support axle assembly with an adjustable lifting de-

vice and raise rear axle assembly until tension is

relieved in control arm being removed.

3.
Disconnect control arm at forward and rearward

attaching points and remove from vehicle.

Bushing Replacement

The upper arm front bushing and carrier ear bushings

are of the same part number and are interchangeable.

CHEVROLET CHASSIS SERVICE MANUAL

REAR SUSPENSION
AND
DRIVE LINE
4-26

DRIVE LINE

REAR AXIE

INDEX

Page

General
Description
4-26

Chevrolet,
Camaro,
Chevelle
and
Chevy
II 4-26

Corvette
4-26

Maintenance
and
Adjustments
4-27

Lubricant
4.37

Lubricant'
Leaks
4_27

Axle Bolts
and
Wheel
Nuts
4-27

Rear Axle Noise
Diagnosis
4-29

Gear Noise
4_29

Bearing
Noise
4-29

Failure
Analysis
4^9

Hypoid
Gears
4..3Q

Differential Gears. 4_30

Bearings
....'.
4.30

Component Parts Replacement

(Chevrolet, Chevelle, Camaro and Chevy n ..... 4.30

Axle Assembly ,. . 4_30

Removal 4 30

Installation * ' 4 3Q
Axle Shaft . . . 4-31

Removal 4-31

Wheel Bolt Replacement 4-31

Oil Seal and/or Bearing Replacement. 4-31

Brake Flange Plate Replacement 4-31

Installation 4-32

Pinion Flange, Dust Deflector and/or

Oil Seal Replacement 4-32

Component Parts Replacement (Corvette) 4-34

Axle Driveshaft .- 4-34

Removal 4-34

Repairs 4-34

Installation. . 4-34

Pinion Flange, Dust Deflector and/or Oil Seal. .... 4-35

Removal 4-35

Inspection . 4-35

Installation .- 4-35

Differential Carrier 4-36

Removal 4-36

Installation 4-36

Positraction Differential Unit-On the Vehicle Check . . 4-37

\

GENERAL DESCRIPTION

CHEVROLET, CHEVELLE, CHEVY
I! AND
CAMARO

The rear axle
(fig. 72) is a
semifloating, fabricated

construction type consisting
of a
cast carrier with large

bosses
on
each
end
into which
two
welded steel tubes

are fitted.
The
carrier contains
an
overhung hypoid

pinion
and
ring gear.
The
differential
is a
two pinion

arrangement.

The axle housing
is
made up
of
two steel welded tubes

pressed into
the
crossbore
of the
cast carrier
-
each

tube
is
puddle welded
at
three places
to the
carrier.

Welded-on brackets provide attachment points
for

Chevelle springs,; shock absorbers,
and
lower control

arms.
Chevrolet models have welded-on brackets
for

control arms,
tie
rod, and shock absorbers. The housing

on Chevy II and Camaro has welded brackets
for
mounting

lower spring
pad
and shock absorber.
A
welded flange
is

provided
for
brake flange plate attachment.

The overhung hypoid drive pinion
is
supported
by
two

preloaded tapered roller bearings.
The
pinion shaft
is

sealed
by
means
of a
molded, spring loaded, rubber seal.

The seal
is
mounted
on the
pinion shaft flange which
is

splined and bolted
to
the hypoid pinion shaft.

The hypoid ring gear
is
bolted
to a
one-piece differen-

tial case which
is
supported
by two
preloaded tapered

roller bearings.

CORVETTE

The Corvette rear axle
is of the
type where
the dif-
ferential carrier housing enclosing
the
differential
and

hypoid gears
is
supported
on a
crossmember mounted
to

the chassis frame.
The
differential
is
connected through

universal joints
to the
drive shafts
and
wheels
(fig. 73).

The internal components
of the
carrier
are of
conven-

tional design, incorporating
a
hypoid gear
set
with
an

overhung pinion supported
on two
pre-loaded, tapered

roller bearing assemblies,
and a
two-pinion differential

assembly supported
on
tapered roller bearings. Pinion

mounting distance adjustments
are
made through the
use

of shims,
as are the
differential bearing pre-load
and

backlash adjustments.
The
differential side gears drive

two splined yokes which
are
retained laterally
by
snap

rings located on the yoke splined end. The yokes
are
sup-

ported on caged needle bearings pressed into
the
carrier,

adjacent
to the
differential bearings.
A
lip seal, pressed

in outboard
of
the bearings, prevents
oil
leakage and dirt

entry.
The
carrier cover
is
bolted
to the
carrier and

provides accessibility
to the
internal parts.
The
cover

incorporates two integral, reinforced mounting pads which

serve
as the
carrier attaching point
to the
suspension

crossmember,
and an
attaching point
for the
spring

center section. The filler plug
is
located on the right side

of the cover near the bolting flange.

All service operations allow carrier removal without

removing
the
carrier cover. Cover removal
is
not nec-

essary
in any of the
service procedures except
in
the

case
of
complete carrier housing replacement,
as the

carrier and cover
are
serviced
as
an assembly.

CHEVROLET CHASSIS SERVICE MANUAL

REAR SUSPENSION AND DRIVE LINE 4-27

SHIM AND

SERVICE

12

14

Fig.
72—Rear Axle Cross-Section (Chevrolet, Camaro, Chevelle and Chevy II)

1.
Companion Flange

2.
Deflector

3. Pinion Oil Seal

4.
Pinion Front Bearing

5. Pinion Bearing Spacer

6. Differential Carrier

LUBRICANT
7. Differential Case

8. Shim

9. Gasket

10.
Differential Bearing

11.
"Clock

12. Pinion Shaft Lock Bolt
13.
Cover

14.
Pinion Shaft

15.
Ring Gear

16.
Side Gear

17.
Bearing Cap

18.
Axle Shaft
19.
Thrust Washer

20.
Differential Pinion

21.
Shim

22.
Pinion Rear Bearing

23.
Drive Pinion

MAINTENANCE AND ADJUSTMENTS

The lubricant level should be periodically checked and

maintained at level of filler plug with a warm axle. See

the lubrication section of this manual for lubricant

recommendations.

Lubricant Leaks

Lubricant leaks should be checked for at the pinion

flange oil seal, axle wheel bearing seals, lubricant-filler
plug, and carrier cover. Correction of these leaks con-

sists of replacing the defective seals or gaskets involved

as described in this section.

AXLE BOLTS AND WHEEL NUTS

From a safety standpoint, axle housing to rear spring

bolts,
wheel nuts and control arm attaching bolts should

be periodically inspected for secure installation.

CHEVROLET CHASSIS SERVICE MANUAL

REAR SUSPENSION AND DRIVE LINE 4-32

HP?

Fig.
81
—Whed Bearing and/or Oil Seal Installation

4.
Install brake components on flange and connect

hydraulic line to wheel cylinder inlet. See Section 5

for brake assembly procedure.

5. Install axle shaft, brake drum and wheel and tire

assembly.

6. Bleed and. adjust brakes as outlined in Section 5.

Installation

1.
Slide axle shaft into place.

CAUTION: Exercise care that splines on end

of shaft do not damage oil seal and that they

engage with splines of differential side gear/

2.
Install axle shaft "C" lock on button end of axle-

shaft and push shaft outward so that shaft lock seats

in counterbore of differential side gear.

3.
Position differential pinion shaft through case and

pinions, aligning hole in shaft with lock screw hole.

Install lock screw and torque to specifications.

4.
Using a new gasket, install carrier cover and torque

bolts to specifications.

CAUTION: Make sure both gasket surfaces on

carrier and cover are clean before installing

new gasket. Torque carrier cover bolts in a

crosswise pattern to ensure uniform draw on

cover gasket.

5. Fill axle with lubricant to a level even with bottom

of filler hole. See Section 0 for proper lubricant.

6. Install brake drum and wheel and tire assembly.

7. Lower vehicle and test operation of axle.

PINION FLANGE, DUST DEFLECTOR

AND/OR OIL SEAL

Replacement

1.
Raise rear of vehicle and place stand jacks under

frame side rails so that axle hangs freely to allow

sufficient working room.

2.
Check wheels for freedom of rotation.

3.
Separate rear universal joint, tape trunnion bearings

to joint, position propeller shaft to one side and tie

it to frame side rail.

4.
Using Tool J-5853 with Adapter J-5810 and a suitable

socket on the pinion flange nut, rotate the pinion

through several complete revolutions and record the

torque required to keep the pinion turning (fig. 82).

If flange is to be reused, mark pinion and flange for

reassembly in the same relative position.

5. Install Tool J-8614-1 on pinion flange and remove

pinion flange nut and washer (fig. 83). (Position
Fig. 82—Measuring Drive Pinion Bearing Preload

J-8614-1 on flange so that the four notches are

toward flange.) Discard nut and use a new one

upon reassembly.

6. Thread pilot end of Tool J-8614-3 into small O.D.

end of J-8614-2. Then with J-8614-1 installed as

in Step 4, insert J-8614-2 into J-8614-1 and turn

it 45 degrees to locked position. Remove flange by

turning J-8614-3 while holding J-8614-1 (fig. 84).

7. Pry old seal out of bore, using a screw driver or a

hammer and chisel.

8. Inspect pinion flange for smooth oil seal surface,

worn drive splines, damaged ears, and for smooth-

ness of bearing contact surface. Replace if

necessary.

9. If deflector requires replacement, remove by tapping

from flange, clean up stake points; install new de-

flector, and stake deflector at three new equally

spaced positions.

NOTE:
Staking operation must be performed

in such a manner that the seal operating surface

is not damaged.

1.0. Pack the cavity between the seal lips of the pinion

flange oil seal with a lithium-base extreme pressure

lubricant, position seal in bore, then using Tools

J-21468 and J-9458, for light-duty axle and Tool

Fig. 83-—Drive Pinion Nut Removal

CHEVROLET CHASSIS SERVICE MANUAL

REAR SUSPENSION AND DRIVE LINE 4-33

Fig.
84—Drive Pinion Flange Removal

J-21057 for heavy-duty axle, press seal into bore

until it seats against shoulder (figs. 85 and 86).

CAUTION: Pinion oil seal flange must not bot-

tom against "carrier. Press seal into carrier

bore until it seats against internal shoulder -

do not apply unnecessary pressure after seal is

seated. To do so will destroy rubber seat ancl

distort seal. ;

11.
Position and align pinion flange on pinion shaft using

Tools J-9458 and
J-8614-1.
Tool J-9458-1 is

threaded onto pinion shaft and nut tightened against

J-9458-2 to pull flange on shaft (fig. 87). Remove
Fig.
86—Drive Pinion Flange Oil Seal

Installation (Heavy-Duty)

J-9458 after flange is seated.

NOTE: The position of the pinion and flange

was previously marked so that reinstallation

may be made with flange and pinion in same

relative position.

CAUTION: Do not attempt to hammer flange

onto pinion shaft. To do so will damage ring

gear and pinion.

12.

13.

14.

15.
Pack the cavity between end of pinion splines and

pinion flange with a non-hardening sealer (such as

Permatex Type A) prior to installing washer and

nut on pinion.

Install washer and a new self-locking nut on pinion

shaft. Tighten nut to remove end play and continue

alternately tightening in small increments and check-

ing preload with torque wrench until it is the same

as that recorded in Step 4.

Reassemble the rear universal joint, and torque

"V" bolt nuts to specifications.

Lower vehicle to floor and road test for leaks.

Fig.
85—Drive Pinion Flange Oil Seal

Installation (Light-Duty)
Fig.
87—Drive Pinion Flange Installation

CHEVROLET CHASSIS SERVICE MANUAL

REAR SUSPENSION AND DRIVE LINE 4-35

Fig.
91—
Removing Carrier Front Support

PINION FLANGE, DUST DEFLECTOR

AND/OR OIL SEAL

Removal

1.
Raise vehicle and place jackstand under frame to

allow wheels to hang free.

2.
Place 1/2" thick block of wood or steel between

carrier upper surface to rear of companion flange,

and body floor. This will prevent carrier assembly

from twisting upward when front support bracket is

disconnected.

3.
Disconnect carrier front mounting bracket bolt from

frame crossmember.

4.
Remove nut from carrier bracket front bolt and

slide bolt to one side until bolt head contacts floor

well. Mark the floor well at this point and drill a

3/4"
diameter hole - remove bolt.

5. Loosen bracket rear bolt and swing bracket down

and to the rear (fig. 91).

6. Disconnect propeller shaft at transmission and at

companion flange. Slide transmission yoke forward,

and lower propeller shaft down and out.

7. Mark companion flange nut and pinion relative loca-

tion.
This is necessary to reset original pinion

bearing pre-load during reassembly of companion

flange.

8. Attach J-8614-1 companion flange holder and remove

flange nut and washer (fig. 92).

9. Remove companion flange by driving off with brass

drift and hammer (fig. 93).

10.
Using screw driver, pry oil seal out of carrier.

Inspection

Inspect companion flange splines for excessive wear

or twisting and check deflector for looseness. If de-

flector is loose or damaged, break stake marks and

remove. Install new deflector and stake in place.

Installation

1.
Place sealing compound around O.D. of new seal

and install seal in carrier using seal Installer

J-21057 (fig. 94).
Fig.
92—Removing Companion Flange Nut

NOTE:
Seal should be started squarely in bore

to eliminate seal distortion.

2.
Tap seal into position until there is a 1/8" gap be-

tween seal flange and carrier (fig. 95).

3.
Lubricate companion flange splines and tap into

place.

4.
Install companion flange washer and nut, and tighten

nut so that it lines up with mark on pinion.

5. Raise propeller shaft into position and connect to

companion flange and transmission yoke.

6. Place rubber cushion on carrier front mounting

bracket and raise bracket into position and loosely

install nut.

7. Install carrier bracket front bolt. With vehicle at

curb,
torque all affected parts to specifications and

install cotter pin to carrier bracket front bolt.

8. Insert a plastic plug from the inside of the floor

well to prevent dust and water entry.

Fig.
93—Removing Companion Flange

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-16

6Y. Adjust clutch pedal travel as outlined in

Section 7.

SHOES AND LININGS

Organic Linings

NOTE:
If brake drums are worn severely, it

may be necessary to retract the adjusting screw.

To gain access to the adjusting screw star

wheel, knock out the lanced area in the web of

the brake drum using a chisel or similar tool.

Release the actuator from the star wheel by

lifting with a small screw driver and back off

the star wheel with a second screw driver (press

down on the handle to retract shoes).

CAUTION: After knocking out the metal, be

sure to remove it from the inside of the drum .

and clean all metal from the brake compartment.

A new hole cover must be installed when drum

is reinstalled.

Removal

1.
Raise the vehicle and plate on jack stands.

2.
Loosen check nuts at parking brake equalizer suffi-

ciently to remove, all tension from brake cable.

3.
Remove brake drums.

NOTE:
Since there are wheel cylinder piston

stops to prevent pistons from leaving cylinders,

it is not necessary to install wheel cylinder

clamps when brake shoes are removed; however,

brake pedal must not be depressed while drums

are removed.

4.
Unhook brake shoe pull back springs from anchor

pin and link end, using Tool J-8049 (fig. 27).

5. Remove the actuator return spring and link.

6. Remove hold-down pins and springs (fig. 28).

7. Remove the actuator assembly.
NOTE:
The actuator, pivot and override spring

are an assembly. It is not recommended that

they be disassembled for service purposes,

unless they are broken. It is much easier to

assemble and disassemble the brakes by leaving

them intact.

8. Separate the brake shoes by removing adjusting

screw and spring.

9. Remove parking brake lever from secondary brake

shoe (rear only).

Inspection

1.
Clean all dirt out of brake drum using care to avoid

getting dirt into front wheel bearings. Inspect drums

for roughness, scoring or out-of-round. Replace or

recondition drums as required.

2.
Inspect wheel bearings and oil seal, and replace

any necessary parts.

3.
On Chevrolet only:

Carefully pull lower edges of wheel cylinder boots

away from cylinders and note whether interior is

wet with brake fluid. Excessive fluid at this point

indicates leakage past piston cups and a need for

wheel cylinder overhaul or replacement.

NOTE:
A slight amount of fluid is nearly always

present and acts as lubricant for the piston.

4.
Check cylinders with internal boots by carefully pull-

ing a small part of the boot out of the cylinder.

Note whether interior is wet with brake fluid. Ex-

cessive fluid at this point indicates leakage past

piston cups and a need for wheel cylinder overhaul

or replacement.

5. Check all brake flange plate attaching bolts to make

sure that they are tight. Clean all rust and dirt

from shoe contact faces on flange plate (fig. 29),

using fine emery cloth.

Installation

CAUTION: Make certain to install recom-

Fig.
27-Unhooking Pull Back Spring
Fig.
28—Removing Hold-Down Springs and Pins

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-20

boss to the front brakes will not contain a check

valve and spring. .

Removal

1.
Wipe main cylinder and lines clean with a clean

cloth. Place dry cloths below main cylinder area to

absorb any fluid spillage.

2.
Disconnect hydraulic lines at main cylinder. Cover

line ends with clean lint-free material to prevent

foreign matter from entering the system.

3.
Disconnect the push rod from the brake pedal.

4.
Unbolt and remove the main cylinder from the

firewall.

5.
Remove the main cylinder mounting gasket and boot.

6. Remove the main cylinder cover and dump out the

fluid. Pump the remaining fluid from the cylinder

by depressing the push rod.

Disassembly (Fig. 32)

1.
Clamp main cylinder in a bench vice.

2.
Remove push rod retainer.

3.
Remove secondary piston stop bolt from bottom of

front fluid reservoir.

4.
Remove the snap ring retainer and primary piston

assembly. Remove the secondary piston, piston

spring, and retainer by blowing air through the stop

bolt hole. (If no air is available, a piece of wire

may be used. Bend approximately 1/4 inch of one

end into -a right angle, hook the secondary piston

and pull it out.)

5.
Position main cylinder in vice with outlet holes

facing up.

6. Drill a 13/64 inch hole through both check valve

seats.

7 Tap out both seats using a 1/4 - 20 tap.

8. Install a spare brake line tube nut in the outlet

hole.
Place a flat washer on a one inch screw

(threaded to screw into tapped hole), and thread

screw into threaded hole in tube seat. Hold the

screw to keep it from turning and back out the

tube nut. This will remove the tube seat.

9. Repeat Step 8 above on second tube seat.

10.
Remove the check valves and springs from the cavi-

ties beneath the tube seats.

11.
Remove the primary seal, primary seal protector,

and secondary seals from the secondary piston.

Remove the piston extension screw securing the

primary piston spring to the primary piston. Re-

move the spring retainer, primary seal, primary

seal protector, and secondary seal from the pri-

mary piston.

Cleaning and Inspection

1.
Remove main cylinder casting from vice and inspect

the bore for corrosion, pits, and foreign matter.

Be sure that the outlet ports are clean and free of

brass cuttings from the tube seat removal operation.

2.
Inspect the fluid reservoirs for foreign matter.

Check the bypass and compensating ports to the

cylinder bore to insure that they are not restricted.

Do not use wire to check ports.

NOTE: Before washing parts, hands must be

clean. Do not wash hands in gasoline or oil

before cleaning parts. Use soap and water only.

3.
Use Declene or equivalent to clean all metal parts

thoroughly. Immerse parts in the cleaning fluid and
brush with hair brush to remove foreign matter.

Blow out all passages, orifices, and valve holes. Air

dry the parts and place on clean paper or lint-free

clean cloth.

NOTE: Be sure to keep parts clean until re-

assembly. Rewash parts, if there is any occa-

sion to doubt cleanliness.

4.
Check pistons for scratches or other visual damage;

replace if necessary.

Assembly (Fig. 32)

Use care when reassembling the main cylinder check

valves. Improper assembly of the check valve seats

will result in distortion of the seats. If this occurs,

there will be no check valve action and a loss of brake

pedal travel will result; the pedal will have to be pumped

one or more times before actual car braking occurs.

1.
Place the main cylinder in a vice with the outlet

holes facing up. Place the check valve springs, in

the outlet holes. Be sure the springs are seated

in the bottom of the holes. Place new rubber check

valves over the springs, being careful not to dis-

place the springs from the spring seats.

2.
Place new brass tube seats in the outlet holes. Be

sure seats are not cocked as this would cause burrs

to be turned up as the tube seats are pressed in.

. Thread a spare brake line tube nut into the outlet

hole and turn the nut down until the tube seat bot-

toms.
Remove the tube nut and check the outlet hole

for loose burrs, which might have been turned up

when the tube seat was pressed down. Repeat this

process to bottom the second seat.

3.
Put new secondary seals in the two grooves in the

end of the secondary piston assembly. The seal

which is nearest the end will have its lips facing

toward that end. The seal in the second groove

should have its lips facing toward the portion of

the secondary piston which contains the small com-

pensating holes.

4.
Assemble a new primary seal protector and primary

seal over the end of the secondary piston with the

flat side of the seal seats against the seal protector,

and the protector against the flange of the piston

which contains the small compensating holes.

5.
Assemble the new secondary seal into the groove on

the push rod end of the primary piston. The lips of

this seal should face toward the small compensating

holes in the opposite end of the primary piston.

6. Assemble the new primary seal protector and pri-

mary seal on the end of-the primary piston with the

flat side of the. seal seated against the seal protector,

and the protector against the flange on the piston

which contains the compensating holes.

7.
Assemble the spring retainer in one end of the

primary piston spring and the secondary piston

stop in the other end. Place the end of the spring

over the end of the primary piston with the spring

retainer seats inside of the lips of the primary

seal.

8. Remove all cleaning liquid from the threaded hole

in the primary piston. Place the piston extension

screw down through the secondary piston stop and

the primary spring retainer and screw it into the

primary piston until it bottoms out.

9. Coat the bore of the master cylinder with clean

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-21

brake fluid. Coat the primary and secondary seals

on the secondary piston with clean brake fluid. Insert

the secondary piston spring retainer into the sec-

ondary piston spring. Place the retainer and spring

down over the end of the secondary piston until the

retainer locates inside of the lips of the primary

cup.

10.
Hold the master cylinder with the open end of the

bore down. Push the secondary piston into the bore

until the spring seats against the closed end of the

bore.

11.
Position the master cylinder in a vise with the

open end of the bore up. Coat the primary and

secondary seal on the primary piston with clean

brake fluid. Push the primary piston assembly,

spring end first, into the bore of the master cylinder*

Hold the piston down and snap the lock ring into

position in the small groove in the I.D. of the bore.

12.
Push the primary piston down to move the secondary

piston forward far enough to clear the stop screw

hole in the bottom of the front fluid reservoir. Install

the stop screw.

13.
Install reservoir diaphragm in the reservoir cover

and install the cover on the main cylinder. Push

bail wire into position to secure the reservoir cover.

Installation

1.
Assemble the push rod through the push rod retainer,

if it has been disassembled.

2.
Push the retainer over the end of the main cylinder.

Assemble new boot over push rod and press it down

over the push rod retainer. Slide new mounting

gasket into position.

3.
Secure .the main cylinder to the firewall with mount-

ing bolts.

4.
Connect the push rod clevis to the brake pedal with

pin and retainer.

5. Connect the brake lines to the main cylinder.

6. Fill the main cylinder reservoirs to the levels

shown in Figure 8. Bleed the brake system as out-

lined in this section.

7. K necessary, adjust the brake pedal free play as

outlined in this section.

WHEEL CYLINDER (Fig. 33)

The wheel cylinder boots should be removed from a

cylinder body only when they are visibly damaged or

leaking fluid. Wheel cylinders having torn, cut, or heat-

cracked boots should be completely overhauled.

Removal

1.
Raise vehicle and place on jack stands.

Fig.
33-Chevelle Wheel Cylinder—Exploded View

1.
Push Rod Boot 6. Spring

2.
Piston 7. Piston Cup

3. Piston Cup 8. Piston

4.
Housing 9. Push Rod Boot

5. Fluid Inlet
2.
Remove wheel and tire assembly. Back off brake

adjustment, if necessary, and remove drum.

3.
Disconnect brake system hydraulic line from

cylinder.

4.
Remove brake shoe pull back springs.

5. Remove screws securing wheel cylinder to flange

plate. Disengage cylinder push rods from brake

shoes and remove cylinder.

NOTE:
On Chevrolet, it is necessary to re-

move the anchor pin which holds the front wheel

cylinder to flange plate to remove the front

wheel cylinder.

Disassembly

1.
Remove boots from cylinder ends with pliers and

discard boots.

2.
Remove and discard pistons and cups.

Inspection and Cleaning

NOTE:
Staining is not to be confused with

corrosion. Corrosion can be identified as pits

or excessive bore roughness.

1.
Inspect cylinder bore. Check for staining and corro-

sion.
Discard cylinder if corroded.

2.
Polish any discolored or stained area with crocus

cloth by revolving the cylinder on the cloth sup-

ported by a finger. Do not slide tfce cloth in a

lengthwise manner under pressure.

NOTE:
Before washing parts, hands must be

clean. Do not wash hands in gasoline or oil

before cleaning parts. Use soap and water to

clean hands.

3.
Wash the cylinder and metal parts in Declene or

equivalent.

4.
Shake excess cleaning fluid from the cylinder-. Do

not use a rag to dry the cylinder as lint from the rag

cannot be kept from the cylinder bore surfaces.

5. Check piston for scratches or other visual damage;

replace if necessary.

Assembly (Fig. 33)

1.
Lubricate the cylinder bore and counterbore with

clean brake fluid and insert spring - expander

assembly.

2.
Install new cups with flat surfaces toward outer

ends of cylinder. Be sure cups are lint and dirt free

before insertion. Do not lubricate cups prior to

assembly.

3.
Install new Durex pistons into cylinder with flat

surfaces toward center of cylinder. Do not lubri-

cate pistons before installation.

4.
Press new boots into cylinder counterbores by hand.

Do not lubricate boots prior to installation.

Installation

1.
Position wheel cylinder to brake flange plate. Install

screws and tighten securely.

NOTE:
On Chevrolet front wheels, mount front

wheel cylinders to the brake flange plate by

installing the threaded anchor pin through the

wheel cylinder housing and tighten to 130 lb. ft.

To secure, peen over the flat washer on the

anchor pin.

CHEVROLET CHASSIS SERVICE MANUAL

ENGINE 6-2

remotely at the starter, with a special jumper

cable or other means, the primary distributor

lead must be disconnected from the negative

post on the coil and the ignition switch must be

in the "ON" position. Failure to do this will

result in a damaged grounding circuit in the

ignition switch.

3.
Crank engine through at least four compression

strokes to obtain highest possible reading.

4.
Check and record compression of each cylinder.

5.
If one or more cylinders read low tor uneven, inject

about a tablespoon of engine oil on top of pistons

in low reading cylinders (through spark plug

port).
Crank engine several times and recheck

compression.

• If compression comes up but does not necessarily

reach normal, rings are worn.

• If compression does not improve, valves are

burnt, sticking or not seating properly.

• If two adjacent cylinders indicate low compres-

sion and injecting oil does not increase compres-

sion, the cause may be a head gasket leak between

the cylinders. Engine coolant and/or oil in cylin-

ders could result from this defect.

NOTE: If a weak cylinder cannot be located

with the compression check, see "Cylinder Bal-

ance Test" under "Additional Checks and Adjust-

ments" in this section.

Service and Install Spark Plugs (Fig. 2)

1.
Inspect each plug individually for badly worn elec-

trodes,
glazed, broken or blistered porcelains and

replace plugs where necessary. Refer to spark plug

diagnosis information presented in Section 6Y for an

analysis of plug conditions.

2.
Clean serviceable spark plugs thoroughly, using an

abrasive-type cleaner such as sand blast. File the

center electrode flat.

3.
Inspect each spark plug for make and heat range. All

plugs must be of the same make and number.

4.
Adjust spark plug gaps to specifications using a

round feeler gauge.
PORCELAIN

INSULATOR

INSULATOR CRACKS

OFTEN OCCUR HERE

CENTER ELECTRODE

[FILE FLAT WHEN

ADJUSTING GAP-

[DO NOT BEND!
(PROPER GAP)

(BEND TO ADJUST GAP)

CAUTION:

adjust gap.
Fig.
2 - Spark Plug Detail

Never bend the center electrode to

Always adjust by bending ground or

side electrode.

If available, test plugs with a spark plug tester.

Inspect spark plug hole threads and clean before in-

stalling plugs. Corrosion deposits can be removed

with a 14 mm. x 1.25 SAE spark plug tap (available

through local jobbers) or by using a small wire brush

in an electric drill. (Use grease on tap to catch

chips.)

ADJUST DWELL

ANGLE SETTING OR

POINT OPENING

Fig.
1 - Checking Compression
Fig.
3 - Distributor (In Line)

CHEVROLET CHASSIS SERVICE MANUAL