Parking Brake Shoe
Friction-lined shoes inside the hat section of a rear brake rotor used to lock the wheels when parked.
Parking brake shoes, also called emergency brake shoes, are the friction-lined components used in the parking brake system of vehicles with rear disc brakes. In these systems, known as a 'drum-in-hat' design, the rear brake rotor has a small hollow drum built into its center hub. The parking brake shoes are mounted inside this drum.
When the driver pulls the parking brake lever or engages the parking brake pedal, a steel cable pulls a mechanical linkage that expands the parking brake shoes outward against the inner surface of the rotor hat, locking the rear wheels in place.
Because parking brake shoes are only applied when the vehicle is stationary, they experience very little wear and can last the life of the vehicle. However, they can wear out if the driver accidentally drives with the parking brake engaged, or if the cable binds. They can also become contaminated with leaking gear oil or axle grease, requiring replacement.