If your truck has a dual parking control valve, you can use pressure from a separate tank to:

Release the spring brakes to move a short distance.. Section 5.1: Dual parking control valves allow you to use air from a separate tank to

If your truck has a dual parking control valve, you can use pressure from a separate tank to:

ANSWER BREAKDOWN
  • A. Correct. Dual parking control valves allow you to use air from a separate tank to release the spring brakes so you can move the vehicle in an emergency.
  • B. Incorrect. "Balance the weight." is not correct. Dual parking control valves allow you to use air from a separate tank to release the spring brakes so you can move the vehicle in an emergency.
  • C. Incorrect. "Cool the engine." is not correct. Dual parking control valves allow you to use air from a separate tank to release the spring brakes so you can move the vehicle in an emergency.
  • D. Incorrect. "Apply the service brakes harder." is not correct. Dual parking control valves allow you to use air from a separate tank to release the spring brakes so you can move the vehicle in an emergency.