brake light CHEVROLET CAMARO 1967 1.G Chassis User Guide

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

BRAKES

SECTION 5

CONTENTS OF THIS SECTION

Duo Servo Brakes

Disc Brakes
Page

5-1 Power Brakes

5-24 Special Tools
Page

5-31

5-32

DUO-SERVO BRAKES

INDEX

Page

General Description 5-1

Maintenance and Adjustments 5-3

Hydraulic Brake Fluid .. . 5-3

Bleeding Hydraulic System 5-3

Pressure Bleeding 5-3

Manual Bleeding 5_4

Push Rod to Main Cylinder Clearance 5-5

Hydraulic Brake Lines 5-5

Hydraulic Brake Hose 5-5

Hydraulic Brake Tubing 5-6

Brake Adjustment. .................... 5-7

Service Brake 5-7

Parking Brake 5-8

Component Replacement and Repairs 5-9

Parking Brake - Chevrolet, Chevelle and

Camaro 5^9

Pedal Assembly 5-9

Front Cable ,. . . 5-9

Center Cable 5-9

Rear Cables. . 5-9
Parking Brake - Chevy n 5-9

Lever Assembly 5-9

Idler Lever 5-11

Front Cable 5-11

Rear Cable . . ; 5-12

Parking Brake - Corvette 5-13

Lever Assembly . . . . 5-13

Front Cable 5-14

Rear Cable . . 5-14

Brake Pedal 5-15

Shoes and Linings 5-16

Organic 5-16

Metallic 5-17

Main Cylinder 5-18

Wheel Cylinders 5-21

Anchor Pin 5-22

Front Wheel 5-22

Rear Wheel 5-22

Brake Drums • 5-22

Brake Pipe Distribution and Switch Assembly . . . . . 5-23

Camaro Pressure Regulator Valve 5-23

GENERAL DESCRIPTION

All 1967 models are equipped with a new split brake

system as a safety feature. If a wheel cylinder or brake

line should fail at either the front end or rear end of

the vehicle, the operator can still bring the vehicle to

a controlled stop. The system is designed with separate

hydraulic systems for the front and rear brake using

a dual master cylinder (fig. 1). The design of the master

cylinder is similar to that used on the 1966 Corvette

in that it has two entirely separate reservoirs and outlets

in a common body casting. The front reservoir and outlet

is connected to the front wheel brakes, and the rear

reservoir and outlet is connected to the rear wheel

brakes. Two pistons within the master cylinder receive

mechanical pressure from the brake pedal push rod and

transmit it through the brake lines as hydraulic pressure

to the wheel cylinders. The filler cap is accessible from

inside the engine compartment.

A new brake pipe distribution and switch assembly

is mounted below the main cylinder. The front and rear

hydraulic brake lines are routed from the main cylinder,

through the brake pipe distribution and switch assembly,

to the front and rear brakes as shown in Figure 2. The

switch is wired electrically to the brake alarm indicator

light on the instrument panel. In the event of fluid loss

in either the front or rear brake system the indicator

on the instrument panel will illuminate red. (The indi-
cator will also' be illuminated when the parking brake is

applied.)

On Camaro models equipped with air conditioning, the

rear brake hydraulic line is routed through a pressure

regulator valve mounted on the left frame side rail

(fig. 3). The valve controls the hydraulic pressure to

the rear brakes resulting in the correct pressure balance

between the front and rear hydraulic systems.

The self-adjusting brakes (fig. 4), used on both front

and rear of all models, are the Duo-Servo single anchor

type which utilize the momentum of the vehicle to assist

in the brake application. The self-energizing or
self-

actuating force is applied to both brake shoes at each

wheel in both forward and reverse motion. The brake

shoe linings are bonded to the shoes.

Wheel cylinders are the double piston type permitting

even distribution of pressure to each brake shoe. To

keep out dust and moisture, both ejads of each wheel

cylinder are sealed with a rubber booC The wheel

cylinders have no adjustments.

The Chevrolet, Chevelle, and Camaro parking brakes

have a foot operated ratchet type pedal mounted to the

left of the steering column. A cable assembly connects

the pedal to an intermediate cable by means of an equal-

izer, where the adjustment for the parking brake is

incorporated. The intermediate cable attaches to the

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES
5-3

PRIMARY

SHOE

PAWL
WIRE LINK

OVERRIDE

LEVER

VERRIDE

SPRING

RETURN

SPRING

STAR
WHEEL

Fig.
3—Camaro
Pressure
Regulator
Valve
Fig.
4-Self-Adjusting
Brake

MAINTENANCE AND ADJUSTMENTS

In any service operation it is extremely important

that absolute cleanliness be observed. Any foreign matter

in the hydraulic system will tend to clog the lines, ruin

the rubber cups of the main and wheel cylinders and

cause inefficient operation or even failure of the braking

system. Dirt or grease on a brake lining may cause

that brake to grab first on brake application and fade

out on heavy brake application.

The split system consists basically of two separate

brake systems. When a failure is encountered on either,

the other is adequate to stop the vehicle. If one system

is not functioning, it is normal for the brake pedal lash

and pedal effort to substantially increase. This occurs

because of the design of the master cylinder which

incorporates ah actuating piston for each system. When

the rear system loses fluid and takes in air, its piston

will bottom against the front piston. When the front

system loses fluid and takes in air, its piston will

bottom on the end of the main cylinders body. The loss

of fluid in one of the systems causes an uneven hydraulic

pressure balance between the front and rear systems.

The brake pipe distribution and switch assembly, near

the main cylinder, detects the loss of pressure and il-

luminates the brake alarm indicator light on the instru-

ment panel. The pressure loss is felt at the brake pedal

by an apparent lack of brakes for most of the brake

travel and then, when failed chamber is bottomed, the

pedal will harden.

HYDRAULIC BRAKE FLUID

Use GM Hydraulic Brake Fluid, Supreme No. 11 or

equivalent when servicing brakes. This brake fluid is

satisfactory for any climate and has all the qualities

necessary for proper operation, such as a high boiling

point to prevent vapor lock and the ability to remain

fluid at low temperatures.
In the event that improper fluid has entered the system,

it will be necessary to service the system as follows:

1.
Drain the entire system.

2.
Thoroughly flush the system with clean alcohol,

188
proof,
or a hydraulic system cleaning fluid

such as "Declene".

3.
Replace all rubber parts of the system, including

brake hoses.

4.
Refill the system.

5. Bleed the system.

BLEEDING HYDRAULIC SYSTEM

The hydraulic brake system must be bled whenever

any line has been disconnected or air has in some way

entered the system. A ''spongy" pedal feeling when the

brakes are applied may indicate presence of air in the

system. The system must be absolutely free of air at

all times. Bleeding should be done on the longest line

first; the proper sequence to follow is left rear, right

rear, right front, and left front (fig. 5). Bleeding of

brake system may be performed by one of two methods—

either pressure or manual.

PRESSURE
BLEEDING

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

cylinder cover and rubber diaphragm.

2.
Reduce fluid level in main cylinder until reservoirs

are approximately half full.

NOTE:
Make sure brake fluid in bleeder equip-

ment is at operating level and that the. equipment

is capable of exerting 30 to 50 lbs. hydraulic

pressure on the brake system.

3.
Install brake bleeder adapter J-22489 (fig. 6) on

main cylinder. Connect hose from bleeder equipment

to bleeder adapter and open release valve on bleeder

equipment.

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 5-8

Fig.
17—-Checking Brake Shoe Lining Clearance

Using Tool J-21177

b.
Turn the tool to the opposite side and fit over

the brake shoes by turning the star wheel, until

the gauge just slides over the linings (fig. 17).

c. Rotate the gauge around the brake shoe lining

surface to assure prpper clearance.

Alternate

a. Using the brake drum as an adjustment fixture

turn the star wheel until the drum slides over

the brake shoes with a slight drag.

b.
Turn the star wheel 1-1/4 turns to retract the

shoes.
This will allow sufficient lining-to-drum

clearance so final adjustment may be made as

described in Step 4.

3.
Install the drum and wheel.

NOTE: 1: If lanced area in brake drum is

knocked out, be sure all metal has been re-

moved from brake compartment. Install new

hole cover in drum to prevent contamination

of the brakes.

NOTE: 2: Make certain when installing drums

that drums are installed in the same position

as when removed with the drum locating tang

in line with the locating hole in the wheel hub

(fig. 18).

4.
Make final adjustment by making numerous forward

and reverse stops, applying brakes with a firm

pedal effort until a satisfactory brake pedal height

results.

NOTE: Frequent usage of an automatic trans-

mission forward range to halt reverse vehic;..$

motion may prevent the automatic adjuster.:?

from functioning, thereby inducing low pedal

heights.
Fig.
.18—Aligning Drum Tang with Wheel Hub

Parking Broke

The rear brake assemblies serve a dual purpose in

that they are utilized both as a hydraulically operated

service brake and also as a mechanically operated

parking brake. In view of this dual purpose, the service

brake must be properly adjusted as a base for parking

brake adjustment; conversely the parking brake must

be properly adjusted for the service brake to function

as intended.

Adjustment

1.
Jack up both rear wheels.

2.
Apply parking brake, two notches from fully re-

leased position.

3.
Loosen the equalizer forward check nut, and tighten

or loosen the rear nut until a light to moderate drag

is felt when rear wheels are rotated.

4.
Tighten check nuts securely.

5.
Fully release parking brake and rotate rear wheels;

no drag should be present.

Inspection

If complete release of the parking brake is not ob-

tained, unless it is forcibly returned to its released

position, or if application effort is high, check parking

brake assembly for free operation. If operation is sticky

or a bind is experienced, correct as follows:

1.
Clean and lubricate brake cables and equalizer.

2.
Inspect brake assembly for straightness and align-

ment (replace if necessary).

3.
Clean and lubricate parking brake assembly.

4.
Check routing of cables for kinks or binding.

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-9

COMPONENT REPLACEMENT AND REPAIRS

PARKING BRAKE-CHEVROLET, CHEVELLE AND

CAMARO (Figs. 19 and 20)

Pedal Assembly

Removal

NOTE:
Remove positive cable from battery to

eliminate the possibility of creating short cir-

cuits under dash.

1.
Place parking brake pedal in released position.

2.
Remove equalizer check nut, and separate cable

stud from equalizer.

3.
Remove two attaching nuts from mounting studs

located in engine compartment.

4.
Remove front cable .ball end from pedal assembly

swivel.

5. Remove pedal assembly to dash brace attaching

screw.

6. Remove pedal assembly by lowering rear slightly

to avoid scratching dash, and pulling, it out of the

firewall.

Installation

1.
Place pedal assembly in position with the two mount-

ing studs protruding through the holes provided in

the firewall.

2.
Install and tighten pedal assembly to dash brace

attaching screw.

3.
Position front cable ball end into pedal assembly

swivel.

4.
Install and tighten two attaching nuts on mounting

studs located in engine compartment.

5. Place
,
equalizer in position on center cable and

insert front cable stud through equalizer and secure

with check nut.

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 the possibility of creating short cir-

cuits under dash.

1.
Place parking brake pedal in released position.

2.
Remove equalizer check nut, and separate cable

, stud from equalizer.

3.
Remove retainer from cable assembly at inner side

of frame rail.

4.
Remove ball end of cable from pedal assembly

swivel.

5. Compress expanded conduit locking fingers at toe

pan arid withdraw cable from car.

6. On Chevelle, if necessary, remove rubber tube

from front cable.

Installation

1.
On Chevelle, if necessary, replace rubber tube

over front cable.

2.
Position cable ball and conduit tip through cutout

in firewall. Make sure conduit locking fingers are

fully expanded and secured in cutout, then position

cable ball into pedal assembly swivel.
3.
Feed stud end of cable through frame rail and se-

cure with retainer on inner side of frame.

4.
Place one check nut on cable stud and insert stud

through equalizer, (make sure center cable is in

position), then place second check nut on stud.

5. Adjust parking brake as outlined in this section.

6. Connect positive battery cable.

Center Cable

Removal

1.
Place parking brake pedal in released position.

2.
Remove equalizer check nut and remove equalizer

from cable.

3.
Remove cable from cable guides.

4.
Disconnect center cable from rear cables at

connectors.

Installation

1.
Install cable ends into rear cable connectors.

2.
Place cable through equalizer and install equalizer

on to front cable stud, secure with check nut. (Do

not tighten.)

3.
Install cable in cable guides (figs. 19 and 20),

4.
Adjust parking brake as outlined in this section.

Rear Cables

Removal

1.
Place parking brake pedal in released position.

2.
Remove equalizer check nut and remove equalizer

from cable.

3.
Remove rear cable from connector.

4.
Remove retainer from rear cable at frame bracket.

Pull cable out of bracket.

5. Remove rear brake drum as outlined in this section.

6. Remove rear brake shoes as outlined in this section.

7. Remove cable end from parking brake actuating

lever.

8. Compress expanded conduit locking fingers at flange

plate entry hole and withdraw cable.

Installation

1.
Pass end of cable and conduit tip through flange

plate entry hole, making sure that conduit locking

fingers all expand fully.

2.
Connect cable end to actuating lever.

3.
Install rear brake shoes, drum and wheel as out-

lined in this section.

4.
Pass cable through frame bracket and install

retainer.

5. Install cable end into cable connector.

6. Position equalizer on center cable and place on

front cable stud, secure with check nut.

7. Make sure all center cable guides are in place

and adjust parking brake as outlined in this section.

PARKING BRAKE-CHEVY II (Fig. 21)

Lever Assembly

Removal

NOTE:
Remove positive cable from battery

to eliminate possibility of creating short cir-

cuits under dash.

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 5-22

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