Which of the following foundation brake parts should be lubricated with chassis grease?

• A. Wheel Cylinders
• B. Brake Drums
• C. S-Cam Bushings
• D. Push Rods

Answer: (C)

In drum-type foundation brakes, lubrication is used only on moving metal-to-metal contact points that could wear or seize. The S-Cam mechanism relies on bushings that allow the cam shaft to rotate smoothly as the brake shoes are spread. These S-Cam bushings should be lubricated with chassis grease to reduce wear, prevent rust, and ensure the cam turns freely so the shoes apply evenly.

The other components aren’t lubricated with grease for safety and performance reasons. Wheel cylinders are hydraulic devices; introducing grease would contaminate the brake fluid and compromise hydraulic braking. Brake drums are the friction surfaces that interact with the shoes, so any grease on them would reduce friction and cause braking problems. Push rods aren’t targeted for chassis grease in typical brake maintenance, as their function is mechanical linkage rather than a bearing surface that needs lubrication.

So, the S-Cam bushings are the parts that should be lubricated with chassis grease.