Home › CDL Practice Tests › General Knowledge Questions › Question 15
Why is grease or oil found on a brake drum or inside a wheel a serious defect?
- A.It makes the brake pedal feel softer only
- B.Oil contamination cuts braking friction and can cause pulling or a wheel fire
- C.It means the brakes were recently serviced correctly
- D.It affects only the parking brake
Correct answer
B. Oil contamination cuts braking friction and can cause pulling or a wheel fire
Why
Friction is what stops the truck, and oil-soaked linings cannot grip the drum properly. Contamination also creates a fire risk as brakes heat up, so the leak source and the linings both need attention.
Manual topic: Vehicle Inspection - Brake System · From the General Knowledge practice bank (GK-015).