Drum Brakes (Rear)

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.

DIAGNOSIS AND TESTING - DRUM BRAKE AUTOMATIC ADJUSTER
To properly test the drum brake automatic adjuster, the aide of a helper inside the vehicle to apply the brakes will be necessary.
1. Raise the vehicle.
2. Remove the access plug from the rear adjustment slot in each brake support plate.
3. Insert a thin screwdriver in the adjustment slot and push back the adjustment lever. With the lever in this position, back the star wheel adjustment off approximately 10 notches. This will eliminate the possibility that the brake is at full adjustment, and can be adjusted no further.
4. Remove the screwdriver from the adjustment slot.
5. Watch the star wheel through the adjustment slot, while a helper applies the brake pedal. As the brake shoes apply, the adjustment lever should move downward, turning the star wheel. A definite rotation of the adjuster star wheel can be observed if the automatic adjuster is working properly. If the star wheel does not move as indicated, the brake drum needs to be removed and further inspection of the rear brakes is necessary.
6. If the star wheel is operating properly, readjust the brakes.
7. Reinstall the adjustment slot access plug.
8. Lower the vehicle.