Brake Shoe
The crescent-shaped steel component coated with friction material that is pressed against the inside of a brake drum.
A brake shoe is the friction-generating component of a drum brake system. Unlike disc brakes which use flat brake pads to clamp a rotor from the outside, drum brakes use curved, crescent-shaped brake shoes that expand outward against the inner curved surface of a rotating brake drum.
Brake shoes consist of a curved steel backing plate with a block of heat-resistant, high-friction material bonded or riveted to the surface. When the driver presses the brake pedal, hydraulic fluid activates the wheel cylinder, pushing the brake shoes apart. The friction material grinds against the spinning drum, converting the vehicle's kinetic energy into heat.
Because drum brakes are typically mounted on the rear axle, brake shoes generally last longer than front brake pads (often 50,000 to 100,000 miles) because the rear brakes perform only 30% of the stopping work. Worn brake shoes will eventually wear down to the steel backing, causing scraping, grinding, and severe damage to the brake drum.
When replacing brake shoes, mechanics also inspect and typically replace the hardware kit (retaining springs, adjuster screws, and return springs) to ensure the shoes retract properly and self-adjust as they wear.