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5-1 8
BRAKES-POWER-KELSEY
HAYES
rod is set to the correct height on original assembly.
If the push rod has been replaced or the adjustment
altered, adjust as follows:
(1)
With the piston assembly free in the cylinder
and firmly seated in a released position, hold the push
rod seated against the reaction disc and centered in
the spring of the cylinder.
(2) Adjust the self-locking screw so that the head
of the screw is 0.933 to 0.943 inch from the face of
the vacuum cylinder (Fig. 22). Fabricate a gauge if
necessary to obtain the correct adjustment.
Master Cylinder
The master cylinder can be bled and the push rod
end assembled at the proper length, as described in
the Service Brake Section of this Manual. (The serv-
ice procedures covering the power brake master cyl-
inder are the same as on the conventional master cyl-
inder.)
The master cylinder push rod is a part of the power
brake and is not retained in the master cylinder pis-
ton. On removing the master cylinder from the power
brake, the piston and cups may drop out of the cylin-
der.
To prevent this from happening, proceed as fol-
lows:
(1) Clean all dirt from the master cylinder cover
and
remove
the cover.
(2) Lightly depress the brake pedal and
insert VS"
wire or drill through the large hole in the brake reser-
voir to retain the piston in the master cylinder.
(3) Proceed with the master cylinder recondition-
ing as recommended under Master Cylinder Servic-
ing.
(4)
After reconditioning, reinstall wire in inlet port
for assembly to the power brake.
(5) Lightly apply pedal and remove wire from in-
let port and fill master cylinder.
(6) Install cover and bleed the hydraulic system.
Installation
(1) Holding the master cylinder piston into the cyl-
inder as recommended, place the master cylinder
on
the attaching studs of the brake unit. Tighten nuts to
100 inch pounds.
(2) Place the power brake unit on the mounting
studs of the dash and install four attaching nuts.
Tighten to 100 inch-pounds.
(3) Connect the push rod to the brake pedal link-
age.
(4) Attach the brake line to the master cylinder.
(5) Attach the vacuum hose
to
the power brake.
(6) Remove retaining wire from port of the master
(7)
Fill the master cylinder and bleed the brake
cylinder reservoir.
system.
POWER BRAKE-KELSEY
HAYES
Description
The power brake, used on Chrysler Models (Fig.
23), is a combined vacuum and hydraulic unit which
utilizes engine intake manifold vacuum and atmos-
pheric pressure to provide power assisted application
of the vehicle brakes.
The Kelsey Hayes Power Brake Unit can be identi-
fied by the
twist
lock method used in locking the
housing and cover together, and by the white colored
vacuum check valve assembly.
The power unit provides lighter pedal pressure.
This lighter pressure is obtained in combination with
a reduced pedal travel, which makes it possible to
bring the pedal down to the approximate height to
the accelerator pedal which is at closed throttle condi-
tion. Thus the driver, after closing the throttle, can
shift his toe from one pedal to the other without lift-
ing his heel from the floor.
The power brake, which is a self contained unit,
eliminates all external rods and levers, and mounts
on the engine side of the dash panel.
The power brake is externally connected to the
brake system at three points. The unit is connected
by a pedal push rod to the brake pedal, by a vacuum
line to the intake manifold (through a vacuum check
valve) and a hydraulic tube from the master cylinder
to the wheel units.
SERVICE PROCEDURES
Removal
(1)
With the engine turned off, apply the brakes
several times to balance the internal pressure of the
brake.
(2) Disconnect the hydraulic brake line from the
master cylinder.
(3) Disconnect the vacuum hose from the power
brake check valve.
(4) Remove the nut and bolt that attach the power
brake push rod from the pedal linkage.
( 5 )
Remove the nuts and washers that attach the
power brake unit to the dash panel.
(6) Remove the power brake and master cylinder
from the vehicle and place on a service bench for
further disassembly. Remove the plastic mounting
gasket.
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