What Is a Foundation Brake?by Meghan JonesUpdated August 09, 2022
Foundation brakes are components inside a truck wheel which encompass many smaller parts of the brake system.
Foundation Brake Composition
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 Brake Parts include:
- The Spring Actuator
- The Brake Drum
- The Mechanical Brake Mechanism
- The Brake Shoes
- And, the Friction Material
Foundation Brake Types
Foundation brakes are found in vehicles with air brakes, such as large trucks. There are three foundation brake types: “S” cam brakes, wedge brakes, and disc brakes. And a fourth obsolete type called the air over hydraulic brake.
- The "S" cam drum brake is the most popular kind of foundation brake for air brakes.
- Wedge and the Air Over Hydraulic brake are obsolete
- Disc brakes are where brake pads pinch the rotor, a circular steel plate, creating friction which slows the vehicle. Disc brakes do not experience brake fade like the drum brake.
Attempting Maintenance on a Foundation Brake?
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.
Based in Phoenix, Meghan Jones has been writing fiction, nonfiction and poetry since 2002. Her creative work "Invisible Driveways" was published by Destructive Heart Press in 2006. Jones received the Mary A. Hill English Creative Writing Scholarship, and she won the Curios Southwest Writing Contest in 2007. She holds a Bachelor of Arts in English creative writing from Northern Arizona University.