brake fluid CHEVROLET CAMARO 1967 1.G Chassis User Guide

BRAKES 5-4

RF

3

^ FRONT OF

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LF

4
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CZZZIZ3

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LR

1

Fig.
5—Correct Bleeding Sequence

4.
Install brake bleeder wrench, Tool J-21472 on bleed-

er valve at wheel cylinder and install one end of

bleeder hose on bleeder valve (fig. 7).

5.
Pour a sufficient amount of brake fluid into a trans-

parent container to insure that end of bleeder hose

will remain submerged during bleeding. Place the

loose end of bleeder hose into the container. Be

sure the hose end is submerged in the fluid.

6. Open wheel cylinder bleeder valve by turning Tool

J-21472 counterclockwise approximately 1/3 of a

turn and observe flow of fluid at end of bleeder

hose.

7.
Close bleeder valve tightly as soon as bubbles stop

and brake fluid flows in a solid stream from the

bleeder hose.

8. Remove brake bleeder wrench and bleeder hose

from wheel cylinder bleeder valve.

9. Repeat Steps 4 through 8 on the remaining wheel

Cylinders in the correct bleeding sequence (fig. 5).

10.
Disconnect bleeder equipment from brake bleeder

adapter cover J-22489.

NOJE: The main cylinder on certain passenger

car models is tilted upward. When removing

the bleeder adapter on these models, place a

clean dry cloth behind and below the cylinder

to absorb any fluid spillage as the cover is

removed. v
Fig.
7—Bleeding Brakes Using Brake Bleeder

Wrench Tool J-21472

11.
adapter J-22489. Wipe all area

fluid was spilled during adapter

Fig.
6—Brake Bleeder Adapter Tool J-22489—Installed
Remove bleeder

dry of fluid if

removal.

12.
Fill master cylinder reservoirs to within 1/4" of

reservoir rims as shown in Figure 8.

13.
Install main cylinder diaphragm and cover.

MANUAL BLEEDING

1.
Clean all dirt from top of main cylinder and remove

cylinder cover and rubber diaphragm.

2.
Fill main cylinder reservoirs.

3.
Install brake bleeder wrench, Tool J-21472 on bleed-

er valve at wheel cylinder and install one end of

bleeder hose on bleeder valve (fig. 7).

4.
Pour a sufficient amount of brake fluid into a trans-

parent container to insure that end of bleeder hose

will remain submerged during bleeding. Place the

loose end of bleeder hose into the container. Be

sure the hose end is submerged in the fluid.

NOTE: Carefully monitor fluid level at main

cylinder during manual bleeding operations. Do

not bleed enough fluid at one time to drain the

reservoir completely. Replenish the reservoirs

with fluid while bleeding to insure a sufficient

amount of fluid is in the main cylinder at all

times.
To insure that outside air is not sucked

back into the hydraulic system, the bleeder

valve should be closed before the brake pedal

reaches the floor.

5.
Open wheel cylinder bleeder valve by turning Tool

J-21472 counterclockwise approximately 1/3 of a

turn. Slowly depress brake pedal. Just before brake

pedal reaches the end of its travel, close bleeder

valve and allow brake pedal to return slowly to the

fully released position. Repeat this procedure until

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-5

LEVEL CYLINDER

TILTED CYLINDER

Fig.
8—Correct Main Cylinder Fluid Level

expelled brake fluid flows in a solid stream from the

bleeder hose and no bubbles are present, then close

bleeder valve tightly.

6. Remove brake bleeder wrench and bleeder hose from

wheel cylinder bleeder valve.

7. Repeat Steps 2 through 7 on the remaining wheel

cylinders in the correct bleeding sequence (fig. 5).

8. Fill the main cylinder to the levels shown in

Figure 8.

9. Install main cylinder diaphragm and cover.

PUSH ROD TO MAIN CYLINDER CLEARANCE

The brake pedal has a definite stop which is permanent

and not adjustable. This stop consists of a rubber

bumper at the release end of pedal travel. Before

adjusting push rod to main cylinder clearance, make

sure pedal returns to the fully released position freely

and that the pedal retracting spring has hot lost its

tension, then proceed as follows:

1.
Loosen check nut on push rod.

2.
Turn push rod as required to provide correct ad-

justment. Movement of pedal pad before push rod

contacts main cylinder pistons must be 1/16" to

1/4" (fig. 9).

3.
Tighten check nut against clevis, and recheck

movement.

HYDRAULIC BRAKE LINES

Hydraulic Brake Hose

The flexible hoses which carry the hydraulic pressure

from the steel lines to the wheel cylinders are carefully

designed and constructed to withstand all conditions of

stress and twist which they encounter during normal

vehicle usage.
The hoses require no service other than periodic

inspection for damage from road hazards or other like

sources. Should damage occur and replacement become

necessary, the following procedure is to be followed.

Removal

1.
Separate hose from steel line by turning double

flare connector out of hose fitting.

2.
Remove "U" shaped retainer from hose fitting and

withdraw hose from support bracket.

3.
Turn hose fitting out of wheel cylinder inlet.

Replacement

1.
Install new copper gasket on cylinder end of hose

(male end).

2.
Moisten threads with brake fluid and install hose in

wheel cylinder inlet.

3.
With weight of car on wheels and suspension in

normal position (front wheels straight ahead) pass

female end of hose through support bracket, allowing

hose to seek its own position. Insert hex of hose

fitting into the 12 point hole in support bracket

in position which induces least twist to hose (figk 10).

NOTE:
Do not twist hose unduly during ^

operation as its natural curvature is absolutely

necessary to maintain proper hose-tot

suspension clearance through full movement o£

the suspension and steering parts.

4.
Install "U" shaped retainer to secure hose in sup-

port bracket.

5. Inspect by removing weight completely from wheel,

turn wheels from lock to lock while observing hose

position. Be sure that hose does not tough other

parts at any time during suspension or wheel travel.

If contact does occur, remove hose retainer and

rotate the female hose end in the support bracket

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-7

LATCH PLATE

DIE BLOCK

TUBE
UPSET FLARE PUNCH

RAM GUIDE

STOP PLATE

Fig.
13—Flaring Operation--Position ing Tubing

2.
Remove the tubing from the die block and deburr

the inside and outside edges.

3.
Install compression couplings on tubing and dip end

of tubing to be flared in hydraulic fluid. This lubri-

cation results in better formation of the flare.

4.
Place on-half of the die blocks in the tool body with

the counterbored ends toward the ram guide. Now

lay the tubing in the block with approximately 1/2"

protruding beyond the end.

Fit the other half of the block into the tool body,

close the latch plate and tighten the nuts "finger

tight".

5. Select the correct size upset flare punch. One end

of this punch is counterbored or hollowed out to

gauge the amount of tubing necessary to form a

double lap flare. Slip the punch into the tool body

with the gauge end toward the die blocks. Install the

ram; then tap lightly until the punch meets the die

, blocks and they are forced securely against the

stop plate (fig. 13).

6. Using the supplied wrench, draw the latch plate

nut down tight to prevent the tube from slipping.

Tightening the nuts alternately (beginning with the

nut at the closed hole in the plate) will prevent

distortion of the plate. Remove the punch and the

ram. Now reverse the punch and put it back into the

tool body. Install the ram and tap it lightly until

the face of the upset flare punch contacts the face

of the die blocks (fig. 14). This completes the

first operation. Remove the ram and the punch.

7. To complete the flare, insert the pointed finish

flare punch and the ram into the tool body. Tap

the ram until a good seat is formed (fig. 15).

NOTE:
The seat should be inspected at inter-

vals during the finishing operation to avoid

over-seating.

LATCH

DIE BLOCK

TUBE
UPSET FLARE PUNCH
RAM GUIDE

RAM
1ST OPERATION

UPSET FLARE

PUNCH
2ND OPERATION

FINISH FLARE

PUNCH

Fig.
15—Flaring Operation—First and Second Flare

BRAKE ADJUSTMENT

Service Brake

Although the brakes are self-adjusting, a preliminary

or initial adjustment may be necessary after the brakes

have been relined or replaced, or whenever the length

of the adjusting screw has been changed. The final

adjustment is made by using the self-adjusting feature.

1.
With brake drum off, disengage the actuator from

the star wheel and rotate the star wheel by spinning

or turning with a small screw driver.

2.
Recommended

a. Use special Tool J-21177; Drum-to-Brake Shoe

Clearance Gauge, to check the diameter of the

brake drum inner surface (fig. 16).

Fig.
14—Flaring Operation—First Flare
Fig.
16—Using Drum-to-Brake Shoe Clearance

Gauge Tool J-21177

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

BRAKES 5-23

Fig.
34—Brake Drum Access Hole

2.

Install brake drum, aligning tang with wheel hub

(fig. 18).

3.
Install wheel and tire assembly.

. 4. Make final brake adjustment as outlined in this

section and check brake operation.

BRAKE PIPE DISTRIBUTION AND SWITCH

ASSEMBLY (Fig. 2)

Removal

1.
Disconnect battery cable.

2.
Disconnect electrical lead from switch assembly.

3.
Place dry rags below the switch to absorb any fluid

spilled during removal of switch.

4.
Disconnect four hydraulic lines from connections
at switch. If necessary, loosen line connections at

main cylinder to loosen lines. Cover open line ends

with clean, lint-free material to prevent foreign

matter from entering the system.

5.
Remove mounting screw and remove switch from

vehicle.

Installation

1.
Make sure new switch is clean and free of dust and

lint. If any doubt exists, wash switch in Declene,

or equivalent, and dry with air.

2.
Place switch in position and secure to bracket with

mounting screw.

3.
Remove protective material from open hydraulic

brake lines and connect lines to switch. If necessary,

tighten brake line connections at main cylinder.

4.
Connect switch electrical lead.

5.
Connect battery cable.

6. Bleed the brake systems as outlined in this section.

CAMARO PRESSURE REGULATOR VALVE

(AIR CONDITIONED MODELS ONLY)

Removal (Fig. 3)

1.
Place dry rags below valve to absorb any fluid

spilled during removal of valve.

2.
Disconnect hydraulic brake lines from both sides

of switch. Cover open line ends with clean, lint-free

material to prevent foreign matter from entering

the system.

3.
Remove mounting screw and remove switch from

vehicle.

Installation

1.
Make sure new valve is clean and free of dust and

lint. If any doubt exists, wash valve in Declene, or

equivalent, and dry with air.

2.
Place valve in position and secure to frame side

rail with mounting screw.

3.
Remove protective material from open hydraulic

brake lines and connect lines to each side of valve.

4.
Bleed brake system as outlined in this section.

CHEVROLET CHASSIS SERVICE

BRAKES
5-24

DISC BRAKES

INDEX

Page

General Description
. 5-24

Maintenance
and
Adjustments
5-24

Bleeding Hydraulic System
5-24

Parking Brake Adjustment
-
Corvette
5-24

Component Replacement
and
Repairs
5-25
Page

Brake Shoes
. . . . . 5-25

Brake Caliper
5-26

Brake Disc
5-29

Main Cylinder.
5-30

Parking Brake Shoes
-
Corvette
5-30

GENERAL DESCRIPTION

Four wheel disc brakes
are
standard equipment
on

the
1967
Corvette,
as in 1966. The
Corvette
may
also

be equipped with heavy duty disc brakes which include

new front calipers, shoes, linings,
and
rear pressure

regulator valve. This heavy duty option
is
used
in

conjunction with
a
vacuum power unit. Front wheel disc

brakes
are
installed
as
optional equipment
on
Chevrolet,

Chevelle, Camaro,
and
Chevy
II
models.

The disc brake,
(fig. 35),
consists
of a
fixed caliper,

rotating disc, splash shield,
and
mounting bracket.
The

caliper assembly contains four pistons and two shoe
and

lining assemblies with
the
lining riveted
to the
steel

shoes.
A
seal
and
dust boot
are
installed
on
each piston,

with
a
piston spring
in the
caliper cylinder bore beneath

each piston.
A
retaining pin extends through each caliper

half
and
both shoes
to
hold
the
shoes and linings
in
posi-

tion
in the
caliper.
On
Corvette heavy duty disc brakes,

two retaining cotter pins
are
used
at
each end
of the

caliper
to
secure
the
shoes
and
linings. Machined
sur-

faces within
the
caliper prevent
the
shoe
and
lining
assembly from rotating with
the
brake disc when pres-

sure
is
applied.

The disc, which
has a
series
of air
vent louvers
to

provide cooling,
is
mounted
on the
front wheel-hub.

The caliper straddles
the
disc and mounts
on a
mounting

bracket attached
to the
steering knuckle with
two
bolts.

The Corvette heavy duty option includes
a
pressure

regulator valve mounted
in the
rear brake line just

below
the
main cylinder. Chevrolet, Chevelle, Camaro,

and Chevy
n
models with disc brakes have
a
pressure

regulator valve mounted
in the
front brake line just

below
the
main cylinder. The valve controls
the
hydraulic

pressure
to the
front
or
rear brakes,
as
applicable,

resulting,
in the
correct pressure balance between
the

front
and
rear hydraulic systems. This valve guards

against premature .lock-up
of
front
or
rear wheels when

brakes
are
applied.

Maintenance, adjustment,
and
service operations which

are
not
included
in
this section
are the
same
as for

the Duo-Servo type brakes.

MAINTENANCE
AND
ADJUSTMENTS

BLEEDING HYDRAULIC SYSTEM

The operation
of
bleeding
the
disc brake hydraulic

system
is the
same
as for
Duo-Servo system outlined

in
the
front
of
this section. Note
the
exceptions below

and refer
to
bleeding procedures under Duo-Servo

brakes.

1.
When pressure bleeding equipment
is
used,
the

correct pressure setting
for
bleeding disc brakes

is 10-2.0
lbs. on
Corvette,
and 40 lbs. on all
other

models.

2.
The
front calipers contain
one
bleeder valve.
The

rear calipers
on
Corvette contain two bleeder valves

(one inboard
and one
outboard) which necessitates

the removal
of the
rear wheels
for
bleeding.

3.
Tapping
the
caliper with
a
rawhide mallet
as the

fluid
is
flowing
out may
assist
in
obtaining
a
good

bleeding
job.

4.
On
Chevrolet, Chevelle, Camaro
and
Chevy
II, the

spring loaded
end of the
pressure regulator valve

(fig.
36)
must
be
held (valve
in
open position) while

bleeding. This
is
done
by
depressing
and
holding

in
the
plunger
in the
end
of
the valve either
by
hand,

by taping,
or by
clamping.
PARKING BRAKE-CORVETTE

Adjustment

1.
Raise rear
end of
vehicle
and
place
on
jack stands.

2.
Remove rear wheels.

3/
Loosen brake cables
at the
equalizer until
the
park-

ing brake levers move freely
to the "off"
position

with slack
in the
cables.

4.
Turn
the
disc until
the
adjusting screw can
be
seen

through
the
hole
in the
disc.

5. Insert
an
adjusting tool
or
screw driver through
the

hole
in the
disc
and
tighten
the
adjusting screw
by

moving your hand away from
the
floor
on
both
the

left and right sides
(fig. 37).

6. Tighten until
the
disc will
not
move, then back
off

ten
(10)
notches.

7. Apply
the
parking brake four
(4)
notches from inside

the
car.

8. Tighten
the
brake cables
at the
equalizer
to
produce

a light drag with
the
wheels mounted.

9. Fully release
the
parking brake handle
and
rotate

the rear wheels.
No
drag should be evident with
the

handle released.

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-25

CORVETTE
CHEVELLE-CAMARO-CHEVY II

Fig.
35-Disc Brake-Cutaway View

COMPONENT REPLACEMENT AND REPAIRS

BRAKE SHOES

Shoes 'with bonded linings should be replaced when the

groove in the center of the lining is worn off leaving

approximately 1/16 inch of lining thickness. Shoes with

linings retained by rivets should be replaced when the

lining is worn to approximately .020" thickness over

the rivet heads.

Removal

1.
Siphon 2/3 of the brake fluid from the main cylinder

reservoirs.

CAUTION: If fluid is not removed, insertion

of the new full thickness lining will force the

pistons back into the housing displacing fluid •••

into the master cylinder. This will cause fee

main cylinder to overflow,, Do not drain the

reservoirs completely or air will be pumped

into the system. ~
2.
Raise vehicle and place on jackstands.

3..
Remove wheels.

4.
Remove and discard the cotter pin from the inboard

end of the shoe retaining pin and slide out the re-

taining pin. On Corvette with heavy duty disc brakes,

two retaining pins must be removed, one on each

end of the caliper assembly.

5. Remove the inboard shoe by rotating either end of

shoe out of caliper and pulling shoe out.

6. Insert new shoe with lining into position. Use a

putty knife to push each piston back as the shoe is

inserted as shown in Figure 38.

7. Replace the outboard shoe as described above. When

both caliper shoes have been replaced, install the

shoe retaining pin through outboard caliper
half,

outboard shoe, inboard shoe, and inboard caliper

half.
Insert a new 3/32 x 5/8 plated cotter pin

through the retaining pin and bend back ends of

cotter pin. (On Corvette heavy duty front caliper,

CHEVROLET CHASSIS SERVICE

BRAKES 5-26

PRESSURE

REGULATOR

VALVE

CHEVROLET
PRESSURE

REGULATOR

VALVE

CAMARO

Fig.
36—Pressure Regulator Valve—Chevrolet and Camaro Shown

install two retaining cotter pins, one at each end of

the caliper.)

8. Repeat above procedure at each wheel where shoes

are to be replaced.

9. Refill main cylinder to fluid level shown in Figure

8. If necessary, bleed brake system as outlined in

this section.

10.
Install wheels and lower vehicle.

BRAKE
CALIPER

Removal

1.
Raise vehicle and place on jackstands.
2.
Remove wheel.

3.
On front caliper, disconnect the brake hose at brake

line support bracket. On Corvette rear caliper,

disconnect the brake tubing from the inboard caliper.

Tape the open tube or line end to prevent foreign

matter from entering the system.

4.
Pull cotter pin from end of shoe assembly retaining

pin.
Remove the pin and shoe assembly from the

Fig.
37—Adjusting Parking Brake Shoes
Fig.
38—Replacing Shoe and Lining Assembly

CHEVROLET CHASSIS SERVICE MANUAL