Home › CDL Practice Tests › Air Brakes Questions › Question 43
What happens to stored air capacity if a tank is partly filled with water and oil sludge?
- A.Capacity increases because liquid holds pressure
- B.Usable air volume shrinks, so pressure drops faster with each brake application
- C.Nothing changes in how the brakes feel
- D.The governor cut-in pressure doubles
Correct answer
B. Usable air volume shrinks, so pressure drops faster with each brake application
Why
Liquid takes up space that should hold compressed air, leaving a smaller reserve. The driver may notice the low-pressure warning arriving sooner after repeated applications.
Manual topic: Air Brakes - Air Tanks and Drains · From the Air Brakes practice bank (AB-043).