CDL General Knowledge TestAir Brakes (if applicable)Medium
During a road test, a driver notices that when the service brakes are applied, the vehicle pulls sharply to one side. All tires are properly inflated. What is the most probable cause related to the air brake system?
- AA stuck open air dryer purge valve.
- BAn oil-contaminated air tank.
- CA brake out of adjustment or a faulty brake chamber on one side.
- DA clogged air filter in the air compressor.
Show answer & explanationAnswer & explanation
Correct answer: C. A brake out of adjustment or a faulty brake chamber on one side.
A vehicle pulling to one side during braking indicates an imbalance in braking force. This is commonly caused by a brake being out of adjustment or a malfunction in a brake component (like a brake chamber or slack adjuster) on one side of the vehicle, causing it to brake harder or weaker than the other side.
Why the other options are wrong
- A. A stuck open air dryer purge valve would cause continuous air loss, not a pulling sensation during braking.
- B. Oil in an air tank would affect the system's longevity and performance, but not directly cause a vehicle to pull to one side during braking.
- D. A clogged air filter would reduce compressor efficiency and pressure build-up, but not cause a pulling sensation during braking.
Uneven Braking
A condition where brakes on one side of the vehicle apply with more or less force than the other side, causing the vehicle to pull.
- Can be caused by misadjusted brakes, faulty chambers, or contaminated linings.
- Dangerous, as it can lead to loss of control.
- Requires immediate inspection and repair.
Memory trick: Pulling = Unbalanced Brakes = Danger!