During the air brake check, you push the trailer air supply valve for the whole combination and hear air escaping loudly near the second dolly. What does this suggest?

Pick an answer

1. A leak or bad seal at that dolly's connection, which should be found and fixed before driving
2. This is the normal sound of the system charging and needs no attention
3. The dolly is simply venting excess pressure as designed on every trip
4. The sound means the rearmost trailer's brakes are working better than expected on that trip

Correct!

Not quite. The correct answer is highlighted.