CDL Air Brakes TestInspecting Air Brake SystemsMedium
A driver is inspecting the brake linings on a commercial vehicle with air brakes. Which of the following conditions would require immediate attention and likely brake replacement?
- APresence of oil or grease on the lining surface.
- BEven wear across the entire lining surface.
- CMinor cracking on the lining surface.
- DLining thickness of 1/4 inch.
Show answer & explanationAnswer & explanation
Correct answer: A. Presence of oil or grease on the lining surface.
Oil or grease contamination on brake linings severely reduces their friction capability, leading to brake fade and increased stopping distances. This is a critical safety hazard requiring immediate replacement.
Why the other options are wrong
- B. Even wear is desirable and indicates proper brake function.
- C. Minor cracking may be acceptable depending on severity and depth, but significant cracking or crumbling would be a concern.
- D. 1/4 inch is typically the minimum allowable thickness for many linings, so it's a concern but not necessarily 'immediate attention' if it's still above the absolute minimum.
Brake Lining Contamination
Contamination of brake linings by oil, grease, or brake fluid severely reduces friction and braking effectiveness, creating a significant safety hazard.
- Causes brake fade and increased stopping distances.
- Requires immediate replacement of affected linings.
- Often indicates a leak from seals, bearings, or brake chambers.
Memory trick: Grease or oil? Your brakes will spoil!