Which component acts as the cam in the foundation brake hardware?

Which component acts as the cam in the foundation brake hardware?

• A. S-Cam
• B. Roller
• C. Brake Spider
• D. Pushrod

Answer: (A)

The main idea here is that the cam in foundation drum brakes is the S-Cam. It’s the component shaped like an S that, when rotated by the actuation linkage, pushes the brake shoes outward to press against the drum. The roller is a follower that rides on the cam surface to reduce friction as the cam turns, helping translate that rotation into shoe movement. The brake spider provides the mounting framework for the shoes and cam, and the pushrod delivers the actuation force from the brake chamber to rotate the cam. So the S-Cam is doing the key camming work that spreads the shoes.

The main idea here is that the cam in foundation drum brakes is the S-Cam. It’s the component shaped like an S that, when rotated by the actuation linkage, pushes the brake shoes outward to press against the drum. The roller is a follower that rides on the cam surface to reduce friction as the cam turns, helping translate that rotation into shoe movement. The brake spider provides the mounting framework for the shoes and cam, and the pushrod delivers the actuation force from the brake chamber to rotate the cam. So the S-Cam is doing the key camming work that spreads the shoes.