Drum Brake System: Description and Operation

SHOE DESIGN
This drum brake is an advanced leading/trailing shoe design. The advanced design operates with less total parts yet its performance is equivalent to other drum brakes while providing improved reliability. The operation and servicing of the advanced design brake is much simpler than traditional drum brakes.

WHEEL CYLINDER FORCE
In the leading/trailing brake, the force from the wheel cylinder is applied equally to both shoes. Torque from the brake shoes is transferred through the backing plate, to the axle flange. Adjustment is automatic when the brakes are applied.

UNIVERSAL SPRING
This brake system employs a single universal spring to hold both shoe and lining assemblies to the backing plate and also act as the return spring for both shoe and lining assemblies. Force from the brake shoes is transferred through the fixed anchor and backing plate to the axle flange. Adjustment is automatic and occurs on any service brake application. Also, with leading/trailing brakes, it is normal for the leading (front) shoe to wear at a faster rate than the trailing (rear) shoe. 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.