turn CHEVROLET CAMARO 1967 1.G Chassis Repair Manual

BRAKES 5-11

VIEW A

VIEWB

CAMARO

Fig.
20—Parking Brake System—Camano

1.
Place parking brake lever in released position.

2.
Remove return spring at equalizer.

3.
Remove equalizer check nut, and separate cable

stud from equalizer.

4.
Remove clevis pin clip and pin from idler lever

assembly.

5. Remove two lever dash attaching screws, and remove

lever assembly from vehicle.

Installation

1.
Place lever assembly into position and secure with

the two lever to dash attaching screws.

2.
Place idler lever in position with lever assembly,

align holes and install clevis pin and clip.

3.
Position equalizer on front cable stud and secure

with check nut.

4.
Install return spring at equalizer.

5. Adjust parking brake as outlined under Maintenance

and Adjustments in this section.

6. Connect positive battery cable.

Idler Lever

Removal

NOTE:
Remove positive cable from battery

to eliminate possibility of creating short cir-

cuits under dash.

1.
Place parking brake lever in released' position.
2.
Eemove return spring at equalizer.

3.
Remove equalizer check nut, and separate cable stud

from equalizer.

4.
Remove clevis pin clip and pin from idler lever

assembly.

5. Remove cable ball from idler lever.

6. Remove pivot pin clip and pivot pin, then remove

idler lever from vehicle.

Installation

1.
Place, idler lever into position and secure with

the pivot pin and clip.

2.
Connect cable ball to idler lever.

3.
Place idler lever in position with lever assembly,

align holes and install clevis pin and clip.

4.
Position equalizer on front cable stud and secure

with check nut.

5. Install return spring at equalizer.

6. Adjust parking brake as outlined under Maintenance

and Adjustments in this section.

7. Connect positive battery cable.

Front Cable

Removal

NOTE:
Remove positive cable from battery

to eliminate possibility of creating short cir-

cuits under dash.

1.
Place parking brake lever in released position.

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-12

VIEW B

Fig.
21—Parking Brake System-Chevy II

2.
Remove return spring at equalizer.

3.
Remove equalizer check nut, and separate cable

stud from equalizer.

4.
Remove clamp from underbody guide bracket. (Con-

vertible models only, also remove clamp from guide

bracket at underbody support.)

5. Remove cable retainer from underbody bracket.

6. Compress expanded conduit locking fingers at toe

pan,
remove cable ball from idler lever, and with-

draw cable from car.

Installation

1.
Position cable ball and conduit tip through cutout

in toe pan.. Make sure conduit locking fingers are

fully expanded and secured in cutout, then position

cable ball in idler lever clevis.

2.
Present parking brake lever to one notch.

3.
P}ace retainer in conduit groove so that conduit

end is secure in underbody bracket.

4.
Position cable in guide bracket(s) and secure cable

in bracket with clamp(s).

5. Place one check nut on cable stud and insert stud

into equalizer, then place second check nut on stud.

6. Connect cable return spring.

7. Adjust parking brake as outlined in this section.
8. Connect positive battery cable.

Rear Cable

Removal

1.
Place parking brake lever in released position.

2.
Disconnect front cable return spring at equalizer.

3.
Remove check nut from front cable stud, withdraw

stud from equalizer, and remove equalizer from

rear cable.

4.
Remove retainers from grooves in rear cable con-

duit, and remove cable from bracket.

5. Remove cable from center body bumper bracket

and spring clip at shock absorber lower mount.

6. Back off rear service brakes sufficiently to allow

for drum removal.

7. Remove both rear wheels and drums.

8. Remove secondary brake shoe return spring.

9. Remove secondary brake shoe hold-down spring

and pin.

10.
Remove cable end from parking brake actuating

lever.

11.
Compress expanded conduit locking fingers at flange

plate entry hole and withdraw cable.

CHEVROLET CHASSIS SERVICE MANUAL

Installation

1.
Pass end of cable and conduit tip through flange

plate entry hole, making sure that conduit locking

fingers all expand fully.

2.
Compress retaining spring and place cable end in

actuating lever.

3.
Install secondary shoe hold-down pin and spring.

4.
Install secondary shoe return spring.

5. Install drum and wheel.

6. Snap cable conduit into spring clip at shock ab-

sorber lower mount.

7. Install cable conduit in bracket at center body bump-

er bracket.

8. Position cable conduit ends in cable bracket and

install retainers in grooves.

9. Place equalizer on cable and insert forward cable

stud. Install check nut and return spring.

NOTE:
To perform its intended function, equal-

izer must be free to slide on rear cable. Lubri-

cate cable at equalizer with chassis grease.

10.
Adjust rear service brakes and parking brake as

outlined in this section.
BRAKES 5-13

PARKING BRAKE-CORVETTE (Fig. 22)

Lever Assembly

Removal

1.
Place parking brake lever in the fully released

position.

2.
Under vehicle, unhook and remove return, spring.

3.
Remove rear nut from cable stud at equalizer and

allow front cable to hang down.

4.
Inside vehicle, remove six screws securing cover

to underbody. It is necessary to push the seat

cushion down as shown in Figure 23 to gain access

to the lower mounting screw on each side. Remove

the retainer. Lift the cover upward and to the

rear to allow seal to slide out of cover slot and

remove cover.

5. Remove trim seal from lever (fig. 24).

6. Remove screw and washer securing parking brake

alarm switch to side of lever assembly.

7. Remove four bolts securing lever assembly to under-

body and lift lever assembly upward. Remove lever

forward mounting bracket.

Fig.
22—Parking Brake System—Corvette

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-14

Fig.
23—Removing or Installing Cover Lower Mounting Screws
Fig.
24—Removing or Installing Trim Seal

8. Remove front cable from lever assembly using long

nose pliers as shown in Figure 25. Remove lever

from vehicle.

Installation

1.^
Install front cable in lever assembly using long

nose pliers as shown in Figure 25. Slide slack

cable through hole and place lever assembly in

position.

2.
Place forward mounting bracket in position and

secure plate and lever assembly to underbody with

four mounting bolts.

3.
Secure parking brake alarm switch to side of lever

assembly with washer and screw (fig. 24).

4.
Install trim seal on lever (fig. 24).

5. Insert the end of the trim seal into the slot in the

cover and slide the cover forward and down into

position.

6. Place the retainer in position. Secure retainer and

cover to underbody with six screws. It is necessary

to push the seat cushion down as shown in Figure 23

to gain access to the lower mounting screw hole on

each side.

7. Under vehicle, insert front cable stud through equal-

izer assembly and secure with nut.

8. Install return spring.

9. Adjust parking brake as outlined under Maintenance

and Adjustments in this section.

Front Cable

Removal

1.
Perform the complete parking brake lever removal

procedure above.

2.
Under vehicle, remove nut, washer, and bolt se-

. curing pulley to pulley bracket (fig. 22).

3.
Remove seal grommet from underbody cable hole.

4.
Pull front cable out of vehicle.

Installation

1.
Install seal grommet around front cable.

2.
Slide front cable into position through cable hole

and work seal grommet into installed position.

3.
Under vehicle, loop front cable around pulley wheel

and secure pulley wheel to bracket with bolt, washer,

and nut (fig..22).

4.
Perform the complete parking brake lever installa-

tion procedure above.
Removal

1.
Remove the cable clip retainers on the back side of

the frame rail from each of the rear brake cable

ends.

2.
Disconnect the cable at the rear wheel flange plate.

3.
Remove the cable ball out of the recess in .the brake

lever assembly clevis.

4.
Disconnect the cables at the equalizer connector and

remove the cables.

Installation

1.
Attach the rear cable balls on the rear cable ends

to the rear wheel recess in the brake lever assembly

clevis.

2.
Attach the cable assembly to the rear wheel flange

plate.

3.
Connect the cable assemblies along the frame rail

area.

4.
Insert the cable end through the equalizer and attach

to the equalizer connector.

5. Adjust as outlined under Maintenance and

Adjustments.

6. Lubricate the cables and all moving parts for

trouble-free operation—see Lubrication, Section 0.

Fig.
25—Removing or Installing Front Cable

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-15

Brake Shoes

Refer to parking brake shoe service procedures under

Disc Brakes in this section.

BRAKE PEDAL (Fig. 26)

Removal

NOTE: Refer to Section 1A for removal

air conditioning components if necessary.
of

1.

5.

b.

c.
Disconnect clutch pedal return spring (manual trans-

mission models only).

Disconnect clutch push rod at pedal.

Disconnect brake pedal return spring (Chevelle and

Camaro only).

Disconnect brake pedal from main cylinder push

rod by removing retainer and clevis pin.

Corvette only:

a. Remove steering column from vehicle as outlined

in Section 9.

Support main cylinder frdm inside engine com-

partment and remove four support brace nuts.

Remove four nuts and bolts securing support

plate to bracket and remove support plate.

d. Remove two screws securing bracket to under-

side of instrument panel and lower bracket and

pedals to floor.

Remove retainer from right side of pedal pivot

shaft.

7.
Slide clutch pedal assembly to the left and remove

from support brace.

8. Withdraw brake pedal and all nylon bushings.

Inspection

1.
Clean all metal parts with a good nontoxic cleaning

solvent.

2.
Wipe nylon bushings clean with a clean cloth.
6
CAUTION: Nylon bushings should not be treated

with cleaning agent of any nature.

3.
Inspect all nylon bushings for wear and damage.

4.
Inspect mating surface of bushings for wear and

damage—replace parts as required.

Installation

1.
Lubricate and install nylon bushings on pedal pivot

shaft, right side of support brace cutout, and through

both ends of brake pedal bore.

2.
Chevrolet, Chevy n, and Corvette: Position brake

pedal return spring on pedal arm and place pedal

assembly in support brace. Index return spring in

support brace cutout.

3.
Chevelle and Camaro: Place pedal assembly in

support brace.

4.
Slide pedal pivot shaft through support brace and

brake pedal bore.

5.
Install retainer to right side of pedal pivot shaft.

6. Corvette only:

a. Install bracket with pedal assemblies to underside

of instrument panel with two screws.

b.
Install support plate on bracket with four bolts

and nuts. • • ' •

c. Place main cylinder in position and install four

bracket and cylinder mounting bolts; secure en-

tire assembly with four nuts.

d. Install steering column in vehicle as outlined

in Section 9.

7.
Chevelle and Camaro: Install brake pedal return

spring.

8. On manual transmission models, connect clutch pedal

push rod to pedal bracket and install retainer. In-

stall clutch pedal return spring.

9. Adjust brake pedal free travel as outlined in this

section. Adjust stoplight switch as outlined in Section

CHEVROLET

CHEVELLE

Fig.
26—Brake Pedal Installation

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 5-17

mended shoe and lining assemblies. Otherwise,

serious fade or failure may occur.

1.
Inspect new linings and make certain there are no

nicks or burrs on bonding material on shoe edge

where contact is made with brake flange plate or

on any of the contact surfaces.

NOTE: Keep hands clean while handling brake

shoes.
Do not permit oil or grease to come in

contact with linings.

2.
If working on rear brakes, lubricate parking brake

cable.

3.
On rear brakes only, lubricate fulcrum end of park-

ing brake lever and the bolt with brake lube, then

attach lever to secondary shoe with bolt, spring

washer, lock washer and nut. Make sure that lever

moves freely.

4.
Before installation make certain the adjusting screw

is clean and lubricated properly.

NOTE: Loose adjustment may occur from an

adjusting screw that is not properly operating.

If the lubrication in the adjusting screw as-

sembly is contaminated or destroyed, the ad-

justing screw should be thoroughly cleaned and

lubricated.

5.
Connect brake shoes together with adjusting screw

spring, then place adjusting screw, socket and nut

in position.

CAUTION: Make sure the proper adjusting

screw is used ("L" for left side of vehicle,

"R"
for right side of vehicle). The star wheel

should only be installed with the star wheel

nearest to the secondary shoe and the adjusting

screw spring inserted to prevent interference

with the star wheel.
6. On rear wheels connect parking brake cable to lever.

7.
Secure the primary brake shoe (short lining—faces

forward) first with the hold-down pin and spring

using a pair of pliers. Engages shoes with the wheel

cylinder connecting links.

8. Install and secure the actuator assembly and second-

ary brake shoe with the hold-down pin and spring

using a pair of needle nose pliers. On rear wheels

position parking brake strut and strut spring.

9. Install guide plate over anchor pin.

10.
Install the wire link.

NOTE: Do not hook the wire link over the

anchor pin stud with the regular spring hook

tool. This may damage the cylinder boot seals.

Fasten the wire link to the actuator assembly ;

first, then place over the anchor pin stud by

hand while holding the adjuster assembly in the

full down position.

11.
Install actuator return spring.

NOTE: Do not pry actuator lever to install re-

turn spring. Ease it in place using the end of a

screw driver or other suitable flat tool.

12.
If old brake pull back (return) springs are nicked,

distorted or if strength is doubtful, install new

springs.

13.
Hook springs in shoes using Tool J-8049 by in-

stalling the primary spring from the shoe over the

anchor pin and then spring from secondary shoe

over the wire link end.

14.
Pry shoes away from backing plate and lubricate

shoe contact surfaces with a thin coating of brake

lube (fig. 29).

CAUTION:

facings.
Be careful to keep lubricant off

Fig.
29—Backing Plate Contact Surfaces
15.
After completing installation, make certain the actu-

ator lever functions easily by hand operating the

self-adjusting feature (fig. 30).

1.6. Follow the above procedure for all wheels.

17.
Adjust the service brakes and parking brake as

outlined under "Maintenance and Adjustments" in

this section.

Metallic Linings

Metallic brake linings which use special heat resistant

brake springs are available as an option. Service opera-

tions are the same as for standard brakes; however,

when new linings are installed, the linings should be

seated as described below.

NOTE: Brake shoes with metallic linings re-

quire specially finished brake drums (honed to a

20 micro-inch finish). Metallic linings are not

recommended for service replacement on ve-

hicles with standard brake drums that have not

been honed to specified finish.

Seating Metallic Linings

After the brakes have been adjusted, the following

recommended "lining seating" is as follows:

1.
Make six to eight stops from 30 MPH with moderate

pedal pressure to aid in seating and to mbdulate

any tendency to dive.

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 5-22

2.
Replace ail push rods and pull back springs.

3.
Connect hose or line to wheel cylinder.

NOTE:
If replacing front wheel cylinder, con-

nect hose and inspect installation as outlined in

"Hydraulic Brake Hose Replacement".

4.
Install drum and wheel.

5. Bleed brakes as outlined in this section.

ANCHOR PIN

Front Wheel

1.
Raise front of vehicle and place on jack stands.

2.
Remove wheel and drum as outlined in this section.

3.
Remove brake shoe pull back springs, link and guide

plate.

4.
Disengage anchor pin lock and remove anchor pin by

turning counterclockwise.

5. Place new lock plate on anchor pin and pass pin

through the hole in flange plate and screw into tapped

hole in spindle support.

6. Torque pin to 130 lb. ft. and lock by peening over

washer tabs.

7. Install brake shoe guide plate, link and pull back

springs.

8. Adjust brakes, install drum and wheel as outlined

in this section. Test brake operation.

Rear Wheel

Two type anchor pins are used in production for the

rear wheels. The riveted type is not serviced and if

failure or damage should occur to either the anchor

pin or flange plate, both parts will have to be replaced

and the threaded type anchor pin used.

Threaded Type

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

2.
Remove wheel and drum as outlined in this section.

3.
Remove brake shoe pull back springs, link and guide

plate.

4.
Remove anchor pin retaining nut and washer and

remove pin from flange plate.

5. Position anchor pin to flange plate, install lock

washer and nut, and torque pin to 80 lb. ft.

6. Install brake shoe guide plate, link and pull back

springs.

7. Adjust brakes and install drum and wheel as outlined

in this section.

8. Test brake operation.

BRAKE DRUMS

Front brake drums are the demountable type; that is,

they can be removed without removing the hub. Rear

brake drums are demountable and may be removed

wihtout removing the axle shaft.

A lanced "knock out" area (fig. 34) is provided in

the web of the brake drum for servicing purposes in

the event retracting of the brake shoes is required in

order to remove the drum.

A small screw driver or hooked wire may be inserted

to disengage the automatic adjuster actuating lever so

the star wheel may be turned.

Removal

1.
Raise vehicle and place on jack stand.
2.
Remove wheel and tire assembly, back off brake

adjustment and remove drum.

Inspection and Reconditioning

Whenever brake drums are removed they should be

thoroughly cleaned and inspected for cracks, scores,

deep grooves, and out-of-round. Any of these conditions

must be corrected since they can impair the efficiency

of brake operation and also can cause premature failure

of other parts.

Smooth up any slight scores by polishing with fine

emery cloth. Heavy or extensive scoring will cause

excessive brake lining wear and it will probably be

necessary to rebore in order to true up the braking

surface.

An out-of-round drum makes accurate brake shoe

adjustment impossible and is likely to cause excessive

wear of other parts of brake mechanism due to its

eccentric action.

A drum that is more than .008" out-of-round on the

diameter is unfit for service and should be rebored.

Out-of^round, as well as taper and wear can be ac-

curately measured with an inside micrometer fitted

with proper extension rods.

If drum is to be rebored for use with standard size

brake facings which are worn very little, only enough

metal should be removed to obtain a true smooth braking

surface.

If drum has to be rebored more than .020" over the

standard diameter, it should be rebored to .060" diameter

oversize and the brake facing should be replaced with

.030"
oversize facings.

A brake drum must not be rebored more than .060"

over the maximum standard diameter, since removal

of more metal will effect, dissipation of heat and may

cause distortion of drum. Chevrolet brake facing is

not furnished larger than .030" oversize and this will

not work efficiently in drums bored more than .060"

oversize.

Brake drums may be refinished either by turning or

grinding. Best brake performance is obtained by turning

drums with a very fine feed. To insure maximum lining

life,
the refinished braking surface must be smooth and

free from chatter or tool marks, and run-out must not

exceed .005" total indicator reading.

Cleaning

New brake drums in parts stock are given a light.

coating of rust proofing oil to prevent the formation of

rust on the critical braking surfaces during the time

that the drums are in storage.

This rust proofing oil must be carefully removed

before the drum is placed in service to prevent any

of this oil from getting on the brake shoe facings, which

might cause an extreme brake grab condition.

It is recommended that a suitable volatile, non-toxic,

greaseless type solvent be used to clean the oil from the

braking surface of the new brake drums before they are

•placed in service to insure the cleanest possible surface.

Gasoline or kerosene should not be used as there is

danger that a portion of the diluated oil substance may

be left on the braking surface that may later cause

difficulty.

Installation

1.
Make brake adjustment as outlined in this section.

CHEVROLET CHASSIS SERVICE MANUAL

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