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At what pressure should the low air pressure warning come on during your brake test as you fan down the pressure?
- A.Only when pressure reaches zero
- B.Before pressure falls below 60 psi
- C.At exactly 100 psi
- D.After the spring brakes have already applied
Correct answer
B. Before pressure falls below 60 psi
Why
The warning exists to give you time to stop while you still have full braking, so it must activate on the way down before 60 psi. Waiting for it after the spring brakes pop would make it useless as a warning.
Manual topic: Combination Vehicles - Air Brake Tests · From the Combination Vehicles practice bank (CV-204).