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What should you do before uncoupling the air lines from a trailer you are about to drop?
- A.Pull the gladhands off first while pressure is still feeding the trailer, to save time
- B.Make sure the trailer brakes are set (supply valve in emergency / spring brakes applied) and the landing gear is down, then disconnect lines and stow them properly
- C.Leave the trailer brakes released so the trailer can be moved by hand
- D.Disconnect the electrical cord last, after the trailer is dropped
Correct answer
B. Make sure the trailer brakes are set (supply valve in emergency / spring brakes applied) and the landing gear is down, then disconnect lines and stow them properly
Why
The dropped trailer must be parked on its own spring brakes and landing gear before any connection is broken. Reversing the order can leave a free-rolling trailer the moment the fifth wheel opens.
Manual topic: Combination Vehicles - Air Lines and Gladhands · From the Combination Vehicles practice bank (CV-248).