
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

STEERING
9-32
arm on frame and install mounting bolts, washers
and nuts. No washer is used on Corvette.
Install relay rod to idler arm, ^making certain seal
is on stud. Install and tighten nut.
Install cotter pin.
Refer to torque specifications at rear of manual for'
correct torque values.
Chevy II (Fig. 62}
Removal
1.
Remove cotter pin, nut and washer securing idler
arm to relay rod.
2.
Remove relay rod from idler arm.
3.
If equipped with power steering disconnect power
cylinder shaft from idler arm bracket.
4.
Remove three idler bracket to frame bolts and nuts
and remove bracket and idler arm assembly.
5.
Remove cotter pin, nut, washer and bolt securing the
idler arm to the bracket.
6. Press out the idler arm bushing for replacement.
Installation
NOTE: Installation must be done with front
wheels straight ahead or the car will lead to one
side.
1.
Install idler arm bushing, if previously removed.
NOTE: Make certain the outer sleeve of the
bushing does not protrude above surface of idler
arm.
2.
Reverse removal procedure and torque all nuts ac-
cording to specifications.
PITMAN ARM
Removal
1.
Remove cotter pin from pitman arm ball stud and
remove nut.
2.
Remove relay rod from pitman arm by tapping on
side of rod or arm in which the stud mounts with a
hammer while using a heavy hammer or similar tool
as a backing. Pull down on relay rod to remove
from stud.
3.
Remove pitman arm nut from sector shaft and mark
relation of arm position to shaft.
4.
Remove pitman arm with Tool J-6632 as shown in
Figure 2.
Installation
1.
Install pitman arm on sector shaft, lining up the
• marks made upon removal.
2.
Install sector shaft nut.
3.
Position relay rod on to pitman arm. Install nut.
Continue to tighten arm enough to align castellation
with hole in stud and install cotter pin.
STEERING ARM
If, through collision or other damage, it becomes nec-
essary to remove and replace either steering arm, pro-
ceed as follows:
Removal
1.
Remove tie rod from steering arm as outlined in this
section.
2.
Remove front wheel, hub and brake drum as a unit
by removing hub cap and dust cap, cotter pin from
spindle nut and the spindle nut. Pull assembly to-
ward outside of vehicle. If removal is difficult, it
may be necessary to back off brake adjustment to
increase brake shoe-to-drum clearance; see Hy-
draulic Brake Adjustment, Section 5. On models
with disc brakes, remove caliper and disc.
3.
With wheel and drum assembly or caliper and disc
removed, steering arm retaining bolt heads are ac-
cessible and removal of steering arm from vehicle
may be accomplished by removing retaining nuts.
Installation
1.
Place steering arm in position on vehicle and install
retaining bolts*
2.
Install nuts. Use only the special locknut listed for
this use in the Chevrolet Parts Catalog.
3.
Pack wheel bearings using a high quality wheel
bearing lubricant. Install bearings and wheel-hub-
brake drum assembly removed previously. On disc
brake models, install disc and caliper.
4.
Install keyed washer and spindle nut. Proceed as out-
lined under t{ Front Wheel Bearing Adjustment" in
Section 3.
5.
Install tie rod ball stud in steering arm. Be sure that
the dust cover is in place on ball stud.
6. Install castellated nut on ball stud, tighten securely
and install cotter pin.
7.
Following directions given in Section 3 to check cor-
nering wheel relationship and toe-in; correct as
required.
STEERING DAMPER-CORVETTE
Removal
1.
Remove bolt from damper pivot bracket at relay rod.
2.
Remove nut from damper pivot at frame bracket and
withdraw damper assembly.
Damper is serviced as a unit. Replace damper if
3.
damaged or excessively worn.
Installation
1.
Place piston rod end into frame bracket and install
retainers, bushings, and nut.
2.
Insert cylinder end pivot into relay rod bracket and
install through bolt.
CHEVROLET CHASSIS SERVICE MANUAL

WHEELS AND TIRES 10-3
Fig.
3 - Spof Wear
to cautioning the owner of his driving habits, is to inter-
change tires regularly.
Side
This may be caused by incorrect wheel camber, under-
inflation, high cambered roads or taking corners at too
high a rate of speed.
The first two causes are the most common. Camber
wear can be readily identified because it occurs only on
one side of the treads, whereas underinflation causes
wear on both sides (fig. 2).
There is, of course, no correction for high cambered
roads.
Cornering wear is discussed further on.
Center
This is caused primarily by overinflation pf the tire
(fig. 2). Invisible fabric damage can also be caused by
overinflation.
Uneven
Uneven or spotty wear (fig. 3) is due to such irregu-
larities as unequal caster or camber, bent front or rear
suspension parts, out-of-balance wheels, brake drums
Fig.
4 - Cornering Wear
out-of-round, brakes out-of-adjustment, or other me-
chanical conditions. The remedy in each case consists
of locating the mechanical defect and correcting it.
Cornering
Since the introduction of independent spring front and
rear wheels, improvements in spring suspension have
enabled drivers to negotiate curves at higher rates of
speed with the same feeling of security that they had
with the older cars at lower speeds. Consequently,
curves are being taken at higher speeds with the result
that a type of tire wear called "Cornering Wear" (fig. 4),
frequently appears.
When a car makes an extremely fast turn, the weight
is shifted from a normal loading on all four wheels to an
abnormal load on the tires on the outside of the curve
and a very light load on the inside tires due to centrifugal
force. This unequal loading may have two unfavorable
results.
First, the rear tire on the inside of the curve may be
relieved of so much load that it is no longer geared to
CHEVROLET CHASSIS SERVICE MANUAL

SPECIFICATIONS
2
RIDING HEIGHT MEASUREMENT*
Chevrolet
All Biscayne
and Bel Air 2 and 4
Doors,
All Impala
and
Caprice
4
Doors
and
All Station Wagons
. . . .
All Impala
and
Caprice
2
Doors
. . . . .
5-1/8"
± 1/2"
5-3/8"
± 1/2"
Chevelle
All Sedans
SS Coupe
and
Convertible
El Camino
and
Station W*
1-3/811
± 1/2"
1-1/8"
± 1/2"
..
2" ± 1/2"
Chevy
u
All
4 and 6
Cylinder Standard
2 and 4
Doors,
All Station Wagons,
and 6
Cylinder Nova
4
Door
All
8
Cylinder Standard
2 and 4
Doors,
All
Nova
2
Doors
and 8
Cylinder Nova
4
Door
. . .
3-3/4'
3-1/4'
±
1/2'
±
1/2'
Corvette
With
327 or 427
Engine
. . . .
327 Engine with
A/C or 427
Engine with
A/C,
P.S.,.and
P.B
Convertible with
327
Engine, Hardtop,
A/C, P.S., P.B., and
Powerglide
427 Engine with Optional Suspension
.
2-1/2"
.
2"
1-1/2"
1-1/2"
±
1/2"
±1/2"
±
1/2"
±
1/2"
Camaro
With
230
Engine
..... . . .
With
250
Engine
.... ...
With
283 - 327 and
350 Engine
2-3/4"
2-7/8"
2-5/8"
± 1/2"
± 1/2"
± 1/2"
•Must be within 1/2" from side to side
BOLT TORQUES
TORQUES
Spherical Joint
Upper Stud
Nut
Lower Stud
Nut
Stud
to
Control
Arm Nuts (Service)
Lower Forging
Nut
Steering
Arm
Attaching Nuts
Shock Absorber
Upper Shaft
Nut
Lower Attachment
Bracket
to
Spring Tower
Stabilizer
Bar
Frame Bracket Bolts
Link Nuts
Strut
Rod
Rod
to Arm Nut
Adjustment
Nut
Front Spring
Spring Seat
to
Control
Arm Nuts
Lower Control
Arm
Inner Pivot Nuts
Upper Control Arm
Attaching Nuts
Collar Bolts
Brake Anchor Pin
Drum Brakes
Brake Anchor Bolt
Disk Brakes
Lower Control Arm
Cross Shaft Bolts
Front
Rear .
Wheel Stud Nuts
Chevrolet
50 ft. lbs.
80 ft lbs.
25 ft. lbs.
40 ft. lbs.
50 ft. lbs.
8 ft. lbs.
15 ft. lbs.
—
15 ft lbs.
8 ft. lbs.
70 ft lbs.
80 ft lbs.
115 ft lbs.
75 ft lbs.
45 ft lbs.
130 ft lbs.
—
65 ft lbs.
Chevelle
50 ft lbs.
80 ft lbs.
25 ft. lbs.
—
85 ft lbs.
8 ft lbs.
20 ft lbs.
—
15 ft lbs.
8 ft lbs.
—
80 ft lbs.
50 ft. lbs.
45 ft. lbs.
130 ft lbs.
—
65 ft lbs.
Chevy H
45 ft lbs.
45 ft lbs.
25 ft lbs.
—
65 ft. lbs.
8 ft lbs.
9 ft lbs.
9 ft. lbs.
9 ft. lbs.
10 ft. lbs.
45 ft lbs.
80 ft lbs.
30 ft lbs.
65 ft lbs.
50 ft. lbs.
50 ft lbs.
130 ft lbs.
_
—
65 ft lbs.
Corvette
45 ft lbs.
20 ft lbs.
20 ft lbs.
—
20 ft lbs.
10 ft lbs.
—
10 ft lbs.
10 ft. lbs.
—
95 ft lbs.
35 ft lbs.
40 ft lbs.
75 ft lbs..
70 ft lbs.
135 ft lbs.
75 ft lbs.
Camaro
50 ft lbs.
65 ft lbs.
25 ft lbs.
—
85 ft lbs.
8 ft lbs.
20 ft lbs.
.
—
15 ft. lbs.
8 ft._lbs.
_
85 ft lbs.
50 ft lbs.
45 ft lbs.
130 ft lbs.
_
—
65 ft lbs.
CHEVROLET CHASSIS SERVICE MANUAL

SPECIFICATIONS
5
BRAKES
SECTION
5
Type
Brake Drums
Diameter
Maximum
Out of Rou
Maximum Rebor©
id
Brake Shoes
Width Front
Rear
Length Primary
Secondary
Wheel Cylinder Diameter
Front
Rear
Chevrolet
Chevelle
Chevy
H
Camaro
Duo Servo Self Adjusting
11"
9-1/2
9-1/2
.008"
.060"
2-3/4
2
9-1/4
11-41/64
1-3/16
1
2-1/2
2
9
9-3/4
1-1/8
15/16
1-1/16
7/8
2-1/2
2
9
9-3/4
1-1/8
15/16
Corvette
Disc
2-7/32
5-31/32
1-7/8
1-3/8
TORQUE CHART
APPLICATION
Brake Pipe Distribution
and
Switch Assembly Mounting
Screws
Main Cylinder
to
Firewall
Mounting Nuts
Push
Rod
Clevis
Nut
Brake Hydraulic
Pipe
to
Main
Cylinder
and
Switch Connections
Brake Hose
to
Brake
Assembly Connection
Parking Brake Equalizer
Check
Nut
Hydraulic Brake
Pipe Connections
Rear Brake Hose
to
Rear
Brake Line "T" Connection
Caliper Half Retaining Bolts
Caliper
to
Mounting Bracket
Retaining Bolts
Chevrolet
24
lb. ft
14
lb. ft
100
lb. in.
(Front Line)
115
lb. in.
(Rear Line)
23
lb. ft
85
lb. in.
110
lb. in.
113
lb. in.
130
lb. ft
130
lb. ft
Chevelle
60
lb. in.
24
lb. ft
14
lb. ft
115
lb. in.
23
lb. ft
85
lb. in.
100
lb. in.
(Front)
120
lb. in.
(Rear)
113
lb. in.
130
lb. ft
130
lb. ft
Chevy
n
150
lb. in.
24
lb. ft
14
lb. ft
115
lb. in.
2^
lb. ft
—
100
lb. in.
65
lb. in.
130
lb. ft
130
lb. ft
Camaro
24
lb. ft
14
lb. ft
115
lb. in.
23
lb. ft
85
lb. in.
100
lb. in.
113
lb. in.
130
lb. ft
130
lb. ft
Corvette
90
lb. in.
24
lb. ft.
14
lb. ft.
115
lb. in.
23
lb. ft
70
lb. in.
100
lb. in.
113
lb. in.
130
lb. ft
130
lb. ft
CHEVROLET CHASSIS SERVICE MANUAL