CDL Combination Vehicles TestInspecting Combination VehiclesHard
A driver is conducting a post-trip inspection of a combination vehicle. They observe that one of the trailer's wheel seals is leaking grease onto the wheel and tire. What is the most significant immediate consequence of this issue?
- APotential for brake contamination and reduced braking effectiveness.
- BDamage to the wheel bearing due to excessive lubrication.
- CIncreased fuel consumption from added rolling resistance.
- DReduced tire pressure due to contamination.
Show answer & explanationAnswer & explanation
Correct answer: A. Potential for brake contamination and reduced braking effectiveness.
A leaking wheel seal allows grease from the wheel hub to escape. This grease can get onto the brake linings, drums, or rotors, contaminating them and drastically reducing their ability to create friction. This directly impairs braking effectiveness and creates a significant safety hazard.
Why the other options are wrong
- B. A leaking seal means a loss of lubrication, which will eventually lead to bearing damage from insufficient, not excessive, lubrication.
- C. While some friction might occur, the primary concern is not fuel consumption but brake integrity.
- D. Grease leakage does not directly cause tire pressure reduction.
Wheel Seal Leakage
The escape of lubricating grease or oil from the wheel hub through a damaged or worn wheel seal, often visible on the wheel or tire.
- Indicates a compromised seal on the wheel hub.
- Leaking grease can contaminate brake components.
- Contaminated brakes lead to reduced stopping power.
Memory trick: Grease on the wheel, brakes won't feel!