Foundation brakes are components inside a truck wheel which encompass many smaller parts of the brake system.
Foundation brakes can be found at the end of each axle. The foundation brakes are made up of several components including the spring actuator, the brake drum, and the mechanical brake mechanism, which includes the brake shoes and friction material.
Foundation brakes are found in vehicles with air brakes, such as large trucks. The "S" cam drum brake is the most popular kind of foundation brake for air brakes.
Brake maintenance is vital to proper vehicle function and driver safety. While the adjustments made to a brake system and foundation brakes are best left to professional mechanics, it is the driver's responsibility to ensure this maintenance is given priority; if the foundation brakes are not in working order, the rest of the brake system will not function.
