Home › CDL Practice Tests › Air Brakes Questions › Question 28
What powers the movement that ultimately applies every service brake in a full air system?
- A.Vacuum from the diesel intake
- B.A hand lever in the cab for each axle
- C.Electric motors at every wheel on all trucks
- D.Compressed air stored in the reservoirs
Correct answer
D. Compressed air stored in the reservoirs
Why
The compressor and tanks exist solely to have pressurized air ready the instant the foot valve calls for it. Engine power drives the compressor, but it is the stored air that does the work at the chambers.
Manual topic: Air Brakes - Air Brake System Components · From the Air Brakes practice bank (AB-028).