Home › CDL Practice Tests › Air Brakes Questions › Question 59
Why is 60 psi such an important threshold in an air brake system?
- A.It is the governor cut-out pressure
- B.It is the floor for the low-pressure warning and well above the range where spring brakes start to take over
- C.It is the safety valve opening pressure
- D.It is the maximum pressure allowed in any tank
Correct answer
B. It is the floor for the low-pressure warning and well above the range where spring brakes start to take over
Why
At 60 psi the system still has usable service braking, but the margin is shrinking fast. Below that, continued loss heads toward the 20 to 45 psi range where springs apply and control of the stop is lost.
Manual topic: Air Brakes - Safety Valve and Low Pressure Warning · From the Air Brakes practice bank (AB-059).