Disc Brake System: Description and Operation

Fig 1 Disc Brake Components -- 2WD:

GENERAL INFORMATION
This vehicle is equipped with single piston disc brake calipers. The calipers move laterally on pins that attach the caliper to the mounting adapter. Abutment surfaces machined in the brake shoes and mounting adapter maintain fore and aft alignment. The calipers are fully serviceable components and can be overhauled when necessary.

Non metallic caliper pistons are used for all applications. The pistons are made of a phenolic resin material.

The rotor and hub assembly is supported on the steering knuckle spindle by the wheel bearings. The rotor braking surfaces are ventilated and can be machined to restore surface finish when necessary.

The disc brake shoes are held in position by retaining springs. The inboard shoe spring is an integral part of the shoe. The outboard shoe is spring is removable. Two slide pins secure the caliper to the caliper adapter. The adapter, which is also removable, is attached to the steering knuckle.

Fig. 2 Piston Seal Function:

Disc Brake Lining Wear Compensation
The caliper piston seal controls the amount of piston extension needed to compensate for normal lining wear. In operation, the seal is deflected outward under fluid pressure. When fluid pressure is released, the seal relaxes and retracts the piston. The amount of retraction is determined by lining wear. Generally, the amount is just enough to maintain contact between the piston and inboard shoe and a zero or very slight clearance at the rotor.

The fluid level in the disc brake reservoir will decrease as lining wear occurs. This is a normal condition and only requires that enough fluid be added to restore proper level.