Why should you lock the tractor glad hands to each other (or dummy couplers) when you are not towing a trailer?
A. The connected brake circuit becomes a backup air tank.
B. It will keep dirt and water out of the lines.
C. If you don't, you could never build air pressure.
Answer: B. It will keep dirt and water out of the lines.
If the answers is incorrect or not given, you can answer the above question in the comment box. If the answers is incorrect or not given, you can answer the above question in the comment box.