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After coupling to a trailer that has been parked, what should be drained or checked on its air system during inspection?
- A.Trailer tanks never collect moisture, so nothing is needed
- B.The trailer's brake chambers should be filled with oil
- C.The trailer air tanks should be drained of water/oil buildup as required, and the system should build and hold pressure normally
- D.Only the tractor tanks ever need draining
Correct answer
C. The trailer air tanks should be drained of water/oil buildup as required, and the system should build and hold pressure normally
Why
Trailer reservoirs collect the same moisture and compressor oil as tractor tanks, and frozen or corroded trailer tanks cause brake problems far from home. Draining and a pressure check belong in the trailer inspection.
Manual topic: Combination Vehicles - Trailer Inspection · From the Combination Vehicles practice bank (CV-171).