If you are testing the brakes on a double and the brakes on the rear trailer do not apply, the cause might be:

The shut-off valves on the front trailer are closed.. Section 7.2: If the valves on the front trailer are closed, air cannot get to the

If you are testing the brakes on a double and the brakes on the rear trailer do not apply, the cause might be:

ANSWER BREAKDOWN
  • A. Correct. If the valves on the front trailer are closed, air cannot get to the rear trailer.
  • B. Incorrect. "The engine is off." is not correct. If the valves on the front trailer are closed, air cannot get to the rear trailer.
  • C. Incorrect. "The parking brake is on." is not correct. If the valves on the front trailer are closed, air cannot get to the rear trailer.
  • D. Incorrect. "The road is wet." is not correct. If the valves on the front trailer are closed, air cannot get to the rear trailer.