Why should you back very slowly for the last part of coupling?

• A.Slow backing makes the air lines connect automatically
• B.A hard slam can damage the kingpin and locking mechanism and can knock the trailer forward
• C.Fast backing is only a problem on hills
• D.Speed has no effect if the trailer brakes are set

Why

The fifth wheel and kingpin are strong, but a hard hit can bend parts and shift a trailer standing on its landing gear. Gentle contact lets the jaws close cleanly around the kingpin.

Manual topic: Combination Vehicles - Coupling · From the Combination Vehicles practice bank (CV-004).

Practice this subject as a full test

More Fifth Wheel & Coupling Steps questions

• Before backing under a trailer, what should you first check about the trailer's height?
• What is the correct way to approach a trailer when starting to couple?
• Just before the fifth wheel contacts the trailer apron, what should you do?
• When you first back under and hear the fifth wheel lock, what is the next safety check?
• What does a tug test check after coupling?