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2-4
GROUP 2-BRAKES
EJ
COMMON ADJUSTMENTS AND REPAIRS ..
PARKING BRAKE
LINKAGE ADJUSTMENT
Check the parking brake cables
when the brakes are fully released.
If the cables are loose, adjust them
as follows:
1. Fully release the parking brake
pedal by pushing down on the man-
ual release lever.
2. Raise the car.
3.
Loosen the adjusting nut on
the equalizer rod, then turn the lock
nut in front of the equalizer several
turns forward (Fig. 15, Part 2-2,
Section 3).
4.
Depress the parking brake pedal
slowly until the initial locking posi-
tion is obtained.
5. Turn the adjusting nut forward
against the equalizer until approxi-
mately 100 lbs. of force at the out-
side diameter of the tire is required
to turn the rear wheels.
6. Tighten the lock nut against
the equalizer.
7.
Release the parking brake, and
check to make sure that the brake
shoes return to the fully released
position.
8. Depress the parking brake pedal
with 100 lbs. of pedal force.
9. Release the parking brake again,
and check as in step 7.
10. If the rear brakes do not fully
release, check the cables for kinks
or binds. Free the cables as required.
MASTER CYLINDER PUSH
ROD ADJUSTMENT·
The push rod is designed with a
self-locking adjustment screw to pro-
vide the correct relationship between
the booster piston and the master
cylinder
piston.
The
adjustment
screw is set to the correct height at
the time of the original assembly of
the power unit. Under normal serv-
ice the adjustment screw does not
require any further attention pro-
viding the push rod assembly re-
FIG.
1-Push Rod Adiustment
mains in the original unit. How-
ever, when a new push rod is used,
or the push rod assembly is trans-
ferred to another unit, the distance
from the end of the adjustment
screw to the mounting surface of
the booster body should be checked.
Use either a micrometer depth gauge
to a dimension of 1.200 inch or a
height gauge as shown in Fig. 1.
The details for making a height
gauge are given in Fig. 2.
After assembly of the master cyl-
inder to the power section, the piston
cup in the hydraulic cylinder should
just clear the compensating port hole
when the unit is in the fully released
position. This can be checked by
placing a few drops of brake fluid
over the compensating port and ap-
plying light air pressure to the out-
put port of the master cylinder.
If
air bubbles appear, the port is open.
If
the primary piston cup overlaps
the compensating port, there will be
no flow of air through the compen-
sating port. If this condition exists,
the
adjustment screw should be
turned into the push rod a slight
amount or until the compensating
port is open.
HYDRAULIC SYSTEM BLEEDING
When any part of the hydraulic
system has been disconnected for
repair or replacement, air may get
into the lines and cause spongy pedal
action. Bleed the hydraulic system
after it has been properly connected
to be sure that all air is expelled
from the brake cylinders and lines.
The hydraulic system can be bled
manually or with pressure bleeding
equipment.
MANUAL
BLEEDING
Bleed the longest lines first. Keep
the master cylinder reservoir filled
with new heavy-duty brake fluid dur-
ing the bleeding operation.
Never use the brake fluid which
has been drained from the hy-
draulic system.
1. Position a
3
/s -inch box wrench
on the bleeder fitting on the right
rear brake wheel cylinder. Attach
a rubber drain tube to the bleeder
fitting. The end of the tube should
fit snugly around the bleeder fit-
ting.
2. Submerge the free end of the
tube in a container partially filled
(008)
#
15 OR
#
16 U.S.S. GAUGE SHEET STEEl
I•
2·~------~~
i - - r - - i i
FIG.
2-Push Rod Gauge
Dimensions
H1087-B
with clean brake fluid, and loosen
the bleeder fitting approximately 3A
turn.
3. Push the brake pedal down
slowly through its full travel. Close
the bleeder fitting, then return the
.pedal to the fully-released position.
Repeat this operation until air bub-
bles cease to appear at the sub-
merged end of the tube.
4.
When the fluid is completely
free of air bubbles, close the bleeder
fitting and remove the drain tube.
5. Repeat this procedure at each
brake wheel cylinder in order: left
rear, right front, and left front. Re-
fill the master cylinder reservoir af-
ter each brake cylinder is bled and
when the bleeding operation is com-
pleted. The fluid level should be
within Vs -inch of the top of the
reservoir.
PRESSURE BLEEDING
Bleed the longest lines first. Never
use brake fluid which has been
drained from the hydraulic sys-
tem.
The bleeder tank should contain
enough new heavy-duty brake fluid
to complete the bleeding operation,
and it should be charged with 10-
30 pounds of air pressure.
1. Clean all dirt from the master
cylinder reservoir cap.
2. Remove the master cylinder
reservoir cap, install an adapter cap
to the reservoir, and attach the
bleeder tank hose to the fitting on
the adapter cap.
Adapter cap 2162 can be used,
or an adapter cap can be fabricated
by cutting a hole in the center of a
filler cap and soldering a fitting at
the hole.
3. Position a Vs -inch box wrench
on the bleeder fitting on the right
rear brake wheel cylinder. Attach a
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