
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 5-4
RF
3
^ FRONT OF
~ VEHICLE
LF
4
RR
CZZZIZ3
2
LR
1
Fig.
5—Correct Bleeding Sequence
4.
Install brake bleeder wrench, Tool J-21472 on bleed-
er valve at wheel cylinder and install one end of
bleeder hose on bleeder valve (fig. 7).
5.
Pour a sufficient amount of brake fluid into a trans-
parent container to insure that end of bleeder hose
will remain submerged during bleeding. Place the
loose end of bleeder hose into the container. Be
sure the hose end is submerged in the fluid.
6. Open wheel cylinder bleeder valve by turning Tool
J-21472 counterclockwise approximately 1/3 of a
turn and observe flow of fluid at end of bleeder
hose.
7.
Close bleeder valve tightly as soon as bubbles stop
and brake fluid flows in a solid stream from the
bleeder hose.
8. Remove brake bleeder wrench and bleeder hose
from wheel cylinder bleeder valve.
9. Repeat Steps 4 through 8 on the remaining wheel
Cylinders in the correct bleeding sequence (fig. 5).
10.
Disconnect bleeder equipment from brake bleeder
adapter cover J-22489.
NOJE: The main cylinder on certain passenger
car models is tilted upward. When removing
the bleeder adapter on these models, place a
clean dry cloth behind and below the cylinder
to absorb any fluid spillage as the cover is
removed. v
Fig.
7—Bleeding Brakes Using Brake Bleeder
Wrench Tool J-21472
11.
adapter J-22489. Wipe all area
fluid was spilled during adapter
Fig.
6—Brake Bleeder Adapter Tool J-22489—Installed
Remove bleeder
dry of fluid if
removal.
12.
Fill master cylinder reservoirs to within 1/4" of
reservoir rims as shown in Figure 8.
13.
Install main cylinder diaphragm and cover.
MANUAL BLEEDING
1.
Clean all dirt from top of main cylinder and remove
cylinder cover and rubber diaphragm.
2.
Fill main cylinder reservoirs.
3.
Install brake bleeder wrench, Tool J-21472 on bleed-
er valve at wheel cylinder and install one end of
bleeder hose on bleeder valve (fig. 7).
4.
Pour a sufficient amount of brake fluid into a trans-
parent container to insure that end of bleeder hose
will remain submerged during bleeding. Place the
loose end of bleeder hose into the container. Be
sure the hose end is submerged in the fluid.
NOTE: Carefully monitor fluid level at main
cylinder during manual bleeding operations. Do
not bleed enough fluid at one time to drain the
reservoir completely. Replenish the reservoirs
with fluid while bleeding to insure a sufficient
amount of fluid is in the main cylinder at all
times.
To insure that outside air is not sucked
back into the hydraulic system, the bleeder
valve should be closed before the brake pedal
reaches the floor.
5.
Open wheel cylinder bleeder valve by turning Tool
J-21472 counterclockwise approximately 1/3 of a
turn. Slowly depress brake pedal. Just before brake
pedal reaches the end of its travel, close bleeder
valve and allow brake pedal to return slowly to the
fully released position. Repeat this procedure until
CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-5
LEVEL CYLINDER
TILTED CYLINDER
Fig.
8—Correct Main Cylinder Fluid Level
expelled brake fluid flows in a solid stream from the
bleeder hose and no bubbles are present, then close
bleeder valve tightly.
6. Remove brake bleeder wrench and bleeder hose from
wheel cylinder bleeder valve.
7. Repeat Steps 2 through 7 on the remaining wheel
cylinders in the correct bleeding sequence (fig. 5).
8. Fill the main cylinder to the levels shown in
Figure 8.
9. Install main cylinder diaphragm and cover.
PUSH ROD TO MAIN CYLINDER CLEARANCE
The brake pedal has a definite stop which is permanent
and not adjustable. This stop consists of a rubber
bumper at the release end of pedal travel. Before
adjusting push rod to main cylinder clearance, make
sure pedal returns to the fully released position freely
and that the pedal retracting spring has hot lost its
tension, then proceed as follows:
1.
Loosen check nut on push rod.
2.
Turn push rod as required to provide correct ad-
justment. Movement of pedal pad before push rod
contacts main cylinder pistons must be 1/16" to
1/4" (fig. 9).
3.
Tighten check nut against clevis, and recheck
movement.
HYDRAULIC BRAKE LINES
Hydraulic Brake Hose
The flexible hoses which carry the hydraulic pressure
from the steel lines to the wheel cylinders are carefully
designed and constructed to withstand all conditions of
stress and twist which they encounter during normal
vehicle usage.
The hoses require no service other than periodic
inspection for damage from road hazards or other like
sources. Should damage occur and replacement become
necessary, the following procedure is to be followed.
Removal
1.
Separate hose from steel line by turning double
flare connector out of hose fitting.
2.
Remove "U" shaped retainer from hose fitting and
withdraw hose from support bracket.
3.
Turn hose fitting out of wheel cylinder inlet.
Replacement
1.
Install new copper gasket on cylinder end of hose
(male end).
2.
Moisten threads with brake fluid and install hose in
wheel cylinder inlet.
3.
With weight of car on wheels and suspension in
normal position (front wheels straight ahead) pass
female end of hose through support bracket, allowing
hose to seek its own position. Insert hex of hose
fitting into the 12 point hole in support bracket
in position which induces least twist to hose (figk 10).
NOTE:
Do not twist hose unduly during ^
operation as its natural curvature is absolutely
necessary to maintain proper hose-tot
suspension clearance through full movement o£
the suspension and steering parts.
4.
Install "U" shaped retainer to secure hose in sup-
port bracket.
5. Inspect by removing weight completely from wheel,
turn wheels from lock to lock while observing hose
position. Be sure that hose does not tough other
parts at any time during suspension or wheel travel.
If contact does occur, remove hose retainer and
rotate the female hose end in the support bracket
CHEVROLET CHASSIS SERVICE MANUAL

BRAKES 5-9
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 5-11
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