1967 CHEVROLET CAMARO Chassis Workshop 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

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

BRAKES 5-27

CHEVELLE
, CHEVY II AND CAMARO SHOWN

1.
Caliper Belts

2.
Bleeder Valve

3. Caliper Half

4.
Piston Spring
Fig.
39-Caliper Assembly-Exploded View

5. Seal

6. Piston

7. Piston Boot

8. Brake Shoes
9. "O" Ri

10.
Caliper

11.
Retaining Pin

12.
Cotter Pin

caliper. Two retaining pins must be removed on

heavy duty Corvette front calipers. Identify the

inboard and outboard shoe if they are to be reused.

5. Remove the end of brake hose at bracket by re-

moving U-shaped retainer from the hose fitting and

withdrawing the hose from bracket.

6. Remove the caliper assembly from the mounting

bracket by removing two hex head bolts.

Disassembly (Fig. 39)

1.
Clean exterior of caliper with Declene, or equivalent.

On Chevrolet and Corvette front caliper, remove

brake hose.

2.
Separate the caliper halves by removing the two

large hex head bolts. Remove the two small "O"

rings from the cavities around the fluid transfer

holes in the two ends of the caliper halves.

3.
To free the piston boots so that the pistons may be

removed, push the piston down into the caliper

as far as it will go. Insert a screwdriver blade

under the inner edge of the steel ring in the boot,

and using the piston as a fulcrum, pry the boot from

its seat in the caliper
half.
CAUTION: Use care not to puncture seal when

removing pistons from caliper. ' ~

4.
Remove the pistons and piston springs from the

caliper
half.
Remove the boot and seal from their

grooves in the piston.

Cleaning and Inspection

1.
Clean all metal parts using Declene, or equivalent.

Remove all traces of dirt and grease. Do not use

mineral base solvents to clean brake parts.

2.
Using an air hose, blow out all fluid passages in the

caliper halves, making sure that there is no dirt

or foreign material blocking any of these passages.

3.
Discard all rubber parts. Boots, seals, and "O"

rings should be replaced with new service kit parts.

4.
Carefully inspect the piston bores in the caliper

halves. They must be free of scores and pits. A

scored or otherwise damaged bore will cause leaks

and unsatisfactory brake operation. Replace the

caliper half if either bore is damaged to the extent

that polishing with very fine crocus cloth will not

restore it.

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-28

Fig.
40—Installing Piston in Caliper Bore Using

Tool J-22591
Fig.
41—Installing Boot Seal in Caliper Bore

Using Tool J-22592

5.
Check the fit of the piston in the bore using a feeler

gage.
Clearance should be as follows:

2 1/16 inch Bore .0045 to .010

1 7/8 inch Bore .0045 to .010

1 3/8 inch Bore .0035 to .009

If the bore is not damaged, and the clearance exceeds

either of the upper limits, a new piston will be required.

Assembly

1.
Assemble the seal in the groove in the piston which

is closest to the flat end of the piston. The lip on

the seal must face toward the large end of the

piston. Be sure lips are in the piston groove and do

not extend over the step in the end of the groove.

2.
Place the spring in the bottom of the piston bore.

3.
Lubricate the seal with dean brake fluid.

4.
Install the piston assembly in the bore using appli-

cable piston rign compressor Tool J-22639, 22629

or 22591 as shown in Figure 40. Use care not to

damage the seal lip as piston is pressed past the

edge of the bore. .

5.
Assemble the boot in the groove of the piston closest

to the concave end of the piston. The fold in the boot

must face toward the end of the piston with the seal

on it.

6. Depress the pistons and check that they slide

smoothly into the bore until the end of the piston is

flush with the end of the bore. If not, re check piston

assembly and location of the piston spring and the

seal.

7.
Position applicable boot seal installer Tool J-22592,

J-22628, or J-22638 over the piston and seat the

steel boot retaining ring evenly in the counterbore

as shown in Figure 41. The boot retaining ring must

be flush or below the machined face of the caliper.

Any distortion or uneven seating could allow con-

taminating and corrosive elements to enter the bore.
8. Position the t:O}> rings in the small cavities around

the brake fluid transfer holes in both ends of the

outboard caliper halves. Lubricate the hex head

. bolts with Delco Brake Lube or clip in clean brake

fluid. Fit caliper halves together and secure with

bolts.
Refer to torque specifications in rear of

manual for correct torque valves.

Installation

1.
Carefully mount the assembled caliper over the edge

of the disc. Use a putty knife to depress pistons so

that the caliper can be lowered into position on the

disc (fig. 42). Use care to prevent damage to boots

• on the edge of the disc as the caliper is mounted.

2.
Secure the caliper to the mounting bracket with two

hex head bolts. Refer to torque specifications in

rear of manual for correct torque values.

CAUTION: If replacing old shoe assemblies,

be sure to get the shoes in the same position

from which they were removed. New shoe as-

semblies have an arrow printed on the back,

showing the direction of forward disc rotation.

3.
Install the shoe and lining assemblies as outlined in

this section.

4.
On Chevrolet and Corvette front calipers, place a

new copper gasket on the male end of the front

wheel brake hose. On all models, install brake hose

in the calipers. With the wheels straight ahead,

pass the female end of the brake hose through the

support bracket.

5.
Make sure the tube seat is clean and connect the

break line tube nut to the caliper. Tighten securely.

6. Allowing the hose to seek a normal position, without

twist, insert hex of the hose fitting into the 12-point

hole in the support bracket and secure it in place

with the "V"-shaped retainer. Turn the steering

geometry from lock to lock while observing the hose.

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-29

Fig.
42—Installing Caliper on Disc

Check that the hose does not touch other parts at

any time during suspension or geometry travel.

If contact does occur, remove the U-shaped retainer

and rotate the end of the hose in the support bracket

one or two points in a direction which will eliminate

hose contact. Reinstall the retainer and recheck

for hose contact. If it is satisfactory, place the

steel tube connector in the hose fitting and tighten

securely.

If rear brake caliper is being serviced, connect

brake line to caliper.

Bleed brakes as outlined in this section.

Install wheels and lower vehicle.

BRAKE DISC

Servicing of the disc brakes is extremely critical

due to tolerances required in machining of the brake

disc to insure proper brake operation. In manufacturing

the brake disc, tolerances of the rubbing surfaces for

flatness is .001 and for parallelism is .0005, while

lateral runout of the faces must not exceed .004 total.

The maintenance of these close controls of the shape of

the rubbing surfaces is necessary to prevent brake

roughness. In addition, the surface finish must be non-

directional and maintained at 30-50 micro-inches. This

control of the rubbing surface finish is necessary to

avoid pulls and erratic performance and promote long

lining life and equal lining wear of both left and right

brakes.

tight scoring of the disc surfaces not exceeding .015

in depth, which may result from normal use, is not

detrimental to brake operation.

When the total disc thickness is less than .965 for the

1"
thick disc or 1.215 for the 1-1/4" thick disc, it should

be replaced. Disc thicknesses less than this can permit

the shoes to come out of contact with the shoe abutments

and cause malfunction.

Because performance is not impaired by surface im-

perfection not exceeding .015 deep, refinishing of the

rubbing surface is not necessary.
Fig.
43—Dial Indicating Disc Runout

Since extremely accurate control of the finishing oper-

ation is necessary for proper performance and excess

metal removal can cause malfunction, refinishing of the

rubbing surface is not recommended.

Checking Procedure (Fig. 43)

Front

Tighten the adjusting nut of the wheel bearing until all

play has been removed. It should be just loose enough

to allow the wheel to turn. Clamp a dial indicator to the

caliper so that its button contacts the disc at a point about

1 inch from the outer edge. When the disc is turned, the

indicator reading should not exceed .002 inches. If runout

exceeds this amount the hub and disc assembly should

be replaced. Due to the close tolerances involved it is

not recommended that the front discs be machined or

serviced separately.

After checking the runout, readjust, the wheel bearings

as outlined in Section 3 of this manual.

Rear—Corvette Only

Check the rear wheel bearing end play, as outlined in

Section 4 of this manual. Then dial indicate the disc face.

If lateral runout of the disc exceeds the bearing end play

by .003 inches, the disc should be refaced (not to exceed

.040 inches) or replaced.

Removal

1.
Raise vehicle and remove wheel and tire assembly.

/ 2. Remove brake caliper as outlined in this section.

3.
Drill out the five rivets attaching the disc to the hub

or spindle.

4.
Remove brake disc from vehicle.

5. Complete the removal of the five rivets from the

hub or spindle.

Installation

1.
Install the disc to the hub or spindle aligning the lug

bolts with the holes in the disc.

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-30

CAUTION: Be sure the emergency brake ad-

justing, holes of the spindle and disc are in

alignment.

2.
Install the brake caliper and shoes as outlined in

this section.

3.
Bleed the brakes as outlined in this section.

4.
Install wheel and tire assembly and lower vehicle.

MAIN CYLINDER

The service operations for the main cylinder are the

same as for Duo-Servo main cylinder. Refer to service

procedures under Duo-Servo Brakes.

PARKING BRAKE SHOES

Corvette (Fig. 44)

Removal

1.
Remove tire and wheel assemblies and brake disc

as outlined in this section.

2.
Remove retractor spring at the top of the shoes.

Remove hold down springs on primary and secondary

shoes.

3.
Remove shoes by pulling them away from the anchor

pin.

4.
Remove the adjusting screw spring and adjusting

screw from the shoes.

Installation

1.
Put light coat of lubriplate on pads, backing plate,

and the threads of the adjusting screw.

2.
Attach adjusting screw spring to the bottom hole in

each shoe.

3.
Insert the star wheel between the shoes. (On left

hand brakes, the star wheel goes next to the rear

shoe; on right hand brakes, the star wheel goes next

to
the.
forward shoe).

4.
Install the shoes on the backing plate by spreading

them and placing them around the anchor pin.

5. Install the hold down springs on the hold down nails.
Fig.
44-Exploded View of Parking Brake Shoes

1.
Parking Brake Shoe

2.
Hold Down Spring and Cap

3. Hold Down Pin

4. Actuating Lever

5. Retractor Spring
6. Backing Plate

7. Parking Plate

8. Hold Down Spring and Cap

9. Adjusting Screw Spring

0, Adjusting Screw Assembly

6. Install retractor spring on one shoe and stretch to

other shoe.

CAUTION: Make sure that the lever assembly

which spreads the shoes is located so that the

notches on the lever fit against the shoes.

7. Install disc and caliper as outlined in. this section.

8. Bleed brakes as outlined in this section.

9. Adjust the parking brake as outlined in this section.

10.
Install wheels and lower vehicle.

CHEVROLET CHASSIS SERVICE MANUAL

BRAKES
5-31

POWER BRAKES

INDEX

General Description 5-31

Maintenance
and"
Adjustments 5-31

Inspection . ... 5_31

Lubrication 5-31

Bleeding Instructions . . . 5.31

Air Cleaner Service . . . , 5.31
Page

Component Replacement 5-31

Power Brake Cylinder ......* 5-31

Removal . . 5-31

Disassembly and Assembly See Overhaul Manual

Installation . . . . 5-31

GENERAL DESCRIPTION

The Power Brake Unit is a self-contained hydraulic

and vacuum unit, utilizing manifold vacuum and atmos-

phere pressure for its power.

This unit permits the use of a low brake pedal as well

as less pedal effort than is required with the conventional

(nonpower) hydraulic brake system. Only two external
line connections are necessary -
one
a vacuum connection

from manifold to check valve located on front shell; the

other, a hydraulic connection from the main cylinder

outlet directly into the hydraulic system. The unit is

mounted on the engine side of the fire wall and directly

connected to the brake pedal.

MAINTENANCE AND ADJUSTMENTS

INSPECTIONS

1.
Check vacuum line and vacuum line connections as

well as vacuum check valve in front shell of power

unit for possible vacuum loss.

2.
Inspect all hydraulic lines and connections at the

wheel cylinders and main cylinder for possible

hydraulic leaks.

3.
Check brake assemblies for scored drums, grease

or brake fluid on linings, worn or glazed linings,

and make necessary adjustments.

4.
Check brake fluid level in the hydraulic reser-

voirs.
The reservoirs should be filled to the levels

shown in Figure 8.

5. Check for loose mounting bolts at main cylinder and

at power section.

6. Check air cleaner filter in power piston extension

and replace filter if necessary.

7. Check brake pedal for binding and misalignment

between pedal
-and
push rod.

LUBRICATION

The power brake unit is lubricated at assembly and
needs no further lubrication other than maintaining

normal reservoir fluid level. The reservoir should be

filled as described in this section.

BLEEDING INSTRUCTIONS

The power system may be bled manually or with a

pressure bleeder as outlined in this section. Use only

GM
Supreme 11 Brake Fluid or equivalent. Do not use the

power assist while bleeding. The engine should not be

running and the vacuum reserve should be reduced to

zero by applying the brake several times before starting

the bleeding procedure.

AIR CLEANER SERVICE

Servicing of the air cleaner is recommended and the

element replaced when restriction becomes severe

enough to affect power brake response. At any other

time, if cleaning of the filter is felt necessary, it should

be shaken free of dirt or washed in soap and water and

thoroughly dried.

COMPONENT REPLACEMENT

POWER BRAKE CYLINDER

Removal

1.
Remove vacuum hose from vacuum check valve.

2.
Disconnect hydraulic lines at main cylinder.

Disconnect push rod at brake pedal assembly.

Remove nuts and lock washers securing power unit

to fire wall, and remove power unit from engine

compartment.
3.

4.

NOTE:
Chevy

to fire wall.
has a three stud attachment

Repair procedures for the power cylinder are outlined

in the Brake Section of the Overhaul Manual-for service
of the main cylinder refer to applicable portion of

"Standard Brakes" in this manual.

Installation

1.
Mount the power brake assembly in place and install

the attaching nuts and lock washers.

2.
Attach vacuum line to check valve.

3.
Secure hydraulic lines to main cylinder.

4.
Attach push rod to brake pedal assembly, and check

operation of stop light.

5. Bleed brakes as outlined in this section.

CAUTION: After replacing the unit on the vehi-

cle,
start the engine and allow vacuum to build

up before applying the brake.

CHEVROLET CHASSIS SERVICE