Home › CDL Practice Tests › Air Brakes Questions › Question 121
Why must a driver chock wheels or otherwise secure the vehicle before working under it with the spring brakes released for service?
- A.With the springs caged or released by air, the vehicle may have no parking hold and can roll
- B.Chocks are required only for paperwork
- C.Released brakes increase engine power
- D.The vehicle becomes lighter without air
Correct answer
A. With the springs caged or released by air, the vehicle may have no parking hold and can roll
Why
Maintenance states deliberately defeat the parking system, so an independent physical block must replace it. Many shop injuries trace back to trusting a brake system that was intentionally disabled.
Manual topic: Air Brakes - Spring Brakes and Parking Brakes · From the Air Brakes practice bank (AB-121).