Drum Brake Shoes

While they have been technologically eclipsed by disc brakes, drum brakes still provide reliable service at the rear wheels on many late model trucks and cars. Although they don’t have the fade resistance of disc brakes, the stopping ability of drum brakes is more than adequate at the rear where they have to provide a smaller percentage of braking capacity. They usually have less noise problems and facilitate simpler parking brake design and operation.

Drum brakes consist of a pair of “shoes” that provide the metal frames for the friction linings. The shoes are secured to a backing plate by hold-down springs, and actuated by the pistons in a hydraulic wheel cylinder. When the brakes are applied, the linings press against the friction surface of the brake drum, which encloses the assembly and attaches to the axle or hub, turning with the wheels. Return springs retract the shoes after brake application.

All drum brake assemblies produced since the 1960s have self-adjuster mechanisms that adjust the shoes to compensate for lining wear and to maintain shoe-to-drum clearance. Rear drum brakes also have parking brake linkage that is connected to parking brake cables. The friction lining can be bonded or riveted to the shoes. There are two common brake shoe configurations, non-servo, or leading-trailing design, and duo-servo brakes. While all drum brakes are “self-energizing”, where stopping power is increased by the rotating drum pulling the shoe tighter to the drum, this characteristic is more powerful on duo-servo brakes.

Friction linings wear during use. Vehicle manufacturers have minimum lining thickness specifications, below which the lining cannot safely perform. Besides measuring lining thickness, they should be inspected for cracks, looseness and uneven wear. Linings that are contaminated by leaking brake fluid from a faulty wheel cylinder or gear oil that has passed by a worn axle seal, must be replaced regardless of thickness. Discolored shoes and linings have been overheated, possibly due to fatigued return springs. Uneven wear can be caused by seized wheel cylinder pistons, improper adjustment, a tapered drum, or worn springs.

Regardless of the cause for replacement, we can supply you with drum brake shoes that will restore OE braking performance. The friction material is engineered for each application, so you get stopping power that suits your driving needs. Temperatures inside a brake drum can gradually fatigue brake hardware. For an effective repair, we recommend replacing hold-down and return springs and self-adjuster mechanisms. We offer complete hardware kits as well as drum brake rebuild kits that include the drums, shoes, hardware, and wheel cylinders. The latter replaces all common wear components with parts designed to work together.