Why should the pre-trip air brake check include listening for air leaks around fittings and valves with the engine running?

Pick an answer

1. An audible hiss can reveal a leak that a visual inspection alone might miss
2. Listening for leaks is only useful once the vehicle is already moving down the road
3. It is done only to check the horn's air supply
4. Air leaks are always silent and cannot be detected by ear

Correct!

Not quite. The correct answer is highlighted.