Drum Brake System: Description and Operation

The rear drum brake assembly is a leading/trailing design. When the brakes are applied, the wheel cylinder pistons move both shoes out to contact the drum with enough energy to overcome the rotation of the wheels, slowing and, with continued application, stopping the vehicle.

Adjustment for both the leading and trailing shoes and linings is automatic when the brakes are applied.

It is normal for the leading shoe to wear at a faster rate than the trailing shoe. Reinstall brake shoes in the same position they were removed from. Do not switch the position of shoes that have been in service as this may. render the self-adjustment feature inoperative and result in increased pedal travel.

On some models, the drum is part of the hub and wheel bearing. For service procedures for this type of drum, look for "Drum and Hub Assembly." On other models, the drum is a hubless-type and is bolted onto a separate wheel bearing hub. The hubless drum can be identified by two screws located on top of the drum.