Brake shoes are the friction component within the drum brake system. Commonly applied to both main rear foot brake and also to the handbrake. They are used within drum braking systems, brake shoes sit inside the brake drums on each wheel. When the brake pedal is applied by the driver, hydraulic cylinders apply pressure on the brake shoes and cause them to expand within the drum, creating friction and stopping power.
Brake shoes generally need replacing every 50k miles or so, when friction material is excessively worn or when contaminated by oils or brake fluids. Also excessive hard braking will cause them to deteriorate far sooner. Replacing them as needed is essential for safe motoring.