Drum Brake System: Description and Operation

DESCRIPTION - DRUM BRAKES (REAR)








Rear drum brakes are standard equipment on this vehicle. The rear drum brakes consist of the major components listed in the figure. Other components related to the brake shoes themselves can be seen in the next figure. The rear wheel drum brakes are a two-shoe, internal-expanding type with an automatic adjuster screw. The automatic adjuster screw is actuated each time the brakes are applied and adjustment is made when lining wear permits. The automatic adjuster screw is located directly below the rear brake wheel cylinder.

OPERATION - DRUM BRAKES (REAR)
When the brakes are applied, fluid pressure is sent to each rear drum brake wheel cylinder. The pressure at the wheel cylinder is exerted equally against both cylinder pistons. The piston pressure is transmitted directly to the top of each brake shoe. This forces the shoes out against the inner surface of the brake drum. This causes friction, bringing the vehicle to a stop.
When the brake pedal is released, so is the fluid pressure. The return springs attached to the shoes return the shoes to the released position.
Vehicles with rear drum brakes use the drum brakes as part of the parking brake system also. Refer to Parking Brake for additional information.