Parking Brake; Rear Drum Brake - Jeep Wrangler 1999 Electronic Service Manual

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DESCRIPTION AND OPERATION (Continued)

REAR DRUM BRAKE

The brake systems use a leading shoe (primary)
and trailing shoe (secondary). The mounting hard-
ware is similar but not interchangeable (Fig. 4).
When the brake pedal is depressed hydraulic pres-
sure pushes the rear brake wheel cylinder pistons
outward. The wheel cylinder push rods then push the
brake shoes outward against the brake drum. When
the brake pedal is released return springs attached
to the brake shoes pull the shoes back to there orig-
inal position.

PARKING BRAKE

Parking brake adjustment is controlled by a cable
tensioner mechanism. The cable tensioner, once
adjusted at the factory, should not need further
adjustment under normal circumstances. Adjustment
may be required if a new tensioner, or cables are
installed, or disconnected.
PARKING BRAKE OPERATION
A hand operated lever in the passenger compartment
is the main application device. The front cable is con-
nected between the hand lever and the tensioner. The
tensioner rod is attached to the equalizer which is the
connecting point for the rear cables (Fig. 5).
The rear cables are connected to the actuating
lever on each secondary brake shoe. The levers are
attached to the brake shoes by a pin either pressed
into, or welded to the lever. A clip is used to secure
the pin in the brake shoe. The pin allows each lever
to pivot independently of the brake shoe.
Fig. 4 Brake Components
To apply the parking brakes, the hand lever is
pulled upward. This pulls the rear brake shoe actu-
ating levers forward, by means tensioner and cables.
As the actuating lever is pulled forward, the parking
brake strut (which is connected to both shoes), exerts
a linear force against the primary brake shoe. This
action presses the primary shoe into contact with the
drum. Once the primary shoe contacts the drum,
force is exerted through the strut. This force is trans-
ferred through the strut to the secondary brake shoe
causing it to pivot into the drum as well.
A gear type ratcheting mechanism is used to hold
the lever in an applied position. Parking brake
release is accomplished by the hand lever release
button.
Fig. 5 Parking Brake Components
BRAKES 5 - 5