Q
15. Why should you lock the tractor glad hands (or dummy couplers) to each other when you are not towing a trailer?
Combination Vehiclesmedium
AThe connected brake circuit becomes a back up air tank.
BIf you did not, you could never build system pressure.
CIt will keep dirt and water out of the lines.
Detailed Explanation
The correct answer is "It will keep dirt and water out of the lines.". This is based on federal CDL regulations and safety standards.
Correct Answer: It will keep dirt and water out of the lines.
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