Safety regulations enforce strict mechanical thresholds for commercial vehicle foundation brake parts to ensure reliable stopping performance. Which finding on an S-cam drum brake assembly indicates a critical defect that must be repaired before the vehicle is driven?
- AA manual slack adjuster pushrod that travels 3/4 inch when pulled firmly by hand with the spring brakes released
- Brake shoe friction linings that are soaked with oil and grease leaking past the wheel hub sealAnswer
- CFine heat check cracks on the drum face that do not extend across more than half the width of the friction surface
- DBrake drum friction surface that is completely dry and free from any grease, oil, or scoring
Answer
Brake shoe friction linings that are soaked with oil and grease leaking past the wheel hub seal
Brake linings must be completely free of oil, grease, and brake fluid. Contamination from leaking wheel seals destroys friction capabilities, causes unequal braking and vehicle pulling, creates a fire risk from friction heat, and constitutes an immediate out-of-service safety defect.
Step-by-Step Solution
Key Concept
Foundation Brake Component Defect Identification
Estimated Time:1m 0s