Brake System Service; System Components; Brake Fluid Level; Master Cylinder Removal - Jeep 1987 Wrangler Workshop Manual

BRAKE SYSTEM
BRAKE SYSTEM SERVICE
SYSTEM COMPONENTS
S E E
I.S.
N
O
T
E
S
Wrangler/YJ models are equipped with power
assisted front disc and rear drum brakes. A du-
al reservoir master cylinder and pressure differ-
ential valve are used in the hydraulic system.
The parking brakes are actuated by a foot-op-
erated lever assembly. A cable and equalizer
mechanism connects the lever to the rear
brakes.
Power brake assist is provided by a single dia-
phragm, vacuum operated brake booster. Pin
mounted, slider-type disc brake calipers are
used at the front and self adjusting drum brake
assemblies are used at the rear.
BRAKE FLUID
Use J E E P brake fluid or an equivalent that
meets SAE standard J 1703F and is graded
DOT 3 or DOT 4. This is the only type of brake
fluid recommended for use in Wrangler/YJ
models.
BRAKE FLUID LEVEL
The correct master cylinder fluid level is to with-
in 6 mm (1/4 in) of the reservoir rim. Use the
recommended brake fluid only and do not
overfill the reservoir.
CAUTION:
Avoid contaminating the brake fluid.
Always clean off the master cylinder and cover
before checking fluid level or filling the
reservoir.
MASTER CYLINDER REMOVAL
Disconnect the brake lines at the master cylin-
der. Cap the lines to prevent dirt entry.
Remove the nuts that attach the master cylinder
to the brake booster mounting studs and re-
move the cylinder.
MASTER CYLINDER OVERHAUL
Remove the cylinder cover and drain the fluid
from the reservoirs.
Inspect the rubber diaphragm in the cover. Re-
place the diaphragm if cut, torn or damaged in
any way.
Press the primary piston (2) inward and remove
the snap ring (2).
Remove and discard the primary piston (2).
Remove the secondary piston (5) and spring (8).
Apply air pressure through the cylinder rear
outlet port to push the piston and spring out.
2