Home › CDL Practice Tests › Air Brakes Questions › Question 141
You find grease and oil inside a wheel around the brake drum area. Why is this treated as a serious brake defect?
- A.Oil inside the wheel lubricates the drum and improves stopping
- B.Contamination can reach the linings, cut friction, cause uneven braking, and create a fire risk as the brake heats
- C.It only matters if the outside of the tire is also oily
- D.It proves the wheel bearing has too much grease by design
Correct answer
B. Contamination can reach the linings, cut friction, cause uneven braking, and create a fire risk as the brake heats
Why
Brakes stop by friction, and friction material soaked or splashed with oil cannot grip the drum as designed. The source of the leak must be fixed and contaminated linings addressed, not simply wiped off and ignored.
Manual topic: Air Brakes - Brake Inspection · From the Air Brakes practice bank (AB-141).