Master Cylinder; Power Brake Booster-Typical - Jeep Wrangler 1997 Manual

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DESCRIPTION AND OPER
pedal. The secondary push rod c
to the master cylinder to stroke t
The atmospheric inlet valve is
by the primary push rod. Booste
through a hose attached to an int
at one end and to the booster
other. The vacuum check valve in
is a one-way device that prevents
Power assist is generated by u
differential between normal at
and a vacuum. The vacuum need
ation is taken directly from the
fold . The entry point for atmo
through a filter and inlet valve
housing (Fig . 1) .
The chamber areas forward
phragms are exposed to vacuu
manifold . The chamber areas to
VACUUM
CHECK
VALVE
MASTER
CYLINDER
MOUNTING
STUD (2)
FRONT
DIAPHRAGM
SECONDARY
PUSH ROD
(TO MASTER
CYLINDER)
nnects the booster
e cylinder pistons.
opened and closed
vacuum supply is
ke manifold fitting
heck valve at the
he booster housing
vacuum leak back .
lizing the pressure
ospheric pressure
d for booster oper-
ngine intake mani-
pheric pressure is
at the rear of the
f the booster dia-
from the intake
he rear of the dia-
Fig. 1 Power Brake Booster-Typical
phragms, are exposed to normal atmospheric pres-
sure of 101 .3 kilopascals (14.7 pounds/square in .) .
Brake pedal application causes the primary push
rod to open the atmospheric inlet valve. This exposes
the area behind the diaphragms to atmospheric pres-
sure . The resulting pressure differential provides the
extra apply pressure for power assist .
MASTER CYLINDER
The master cylinder has a removable nylon reser-
voir (Fig. 2) . The cylinder body is made of aluminum
and contains a primary and secondary piston assem-
bly. The cylinder body including the piston assem-
blies are not serviceable. If diagnosis indicates an
internal problem with the cylinder body, it must be
replaced as an assembly . The reservoir and grommets
are the only replaceable parts on the master cylinder .
HOUSING
BOOSTER
MOUNTING
STUDS (4)
SEAL
ATMOSPHERIC
INLET VALVE
ASSEMBLY
PRIMARY
PUSH ROD
(TO BRAKE
PEDAL)
J9505-58