Home › CDL Practice Tests › Air Brakes Questions › Question 48
Why should a driver let a cold engine idle and watch the gauges before moving after start-up?
- A.Moving immediately builds air faster under all conditions
- B.To confirm air builds to normal operating pressure and the low-pressure warning goes out before releasing the brakes
- C.The gauges are only for the mechanic
- D.Idling is required to warm the brake drums
Correct answer
B. To confirm air builds to normal operating pressure and the low-pressure warning goes out before releasing the brakes
Why
Releasing the parking brakes and driving before air is up leaves the driver with weak or no service brakes. Waiting for full build-up and a silent warning is a basic start-up discipline.
Manual topic: Air Brakes - Air Compressor and Governor · From the Air Brakes practice bank (AB-048).