Coupling & UncouplingQuestion 10 of 60
When you push the trailer air supply valve in (supply air to trailer), what should happen?
a.The trailer parking brakes stay locked
b.Air flows to the trailer and the trailer spring brakes release
c.The tractor engine shuts off
d.The fifth wheel unlocks
Explanation
Pushing in the trailer air supply valve sends air to the trailer, which releases the trailer spring (parking) brakes. You should always charge the trailer air and then test the brakes before moving. This step is done after confirming the air lines are connected correctly.
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Related questions on this topic
- When should the locking jaws be closed around the kingpin?
- After the trailer is securely coupled and supported by the tractor, what should you do with the landing gear?
- Before supplying air to the trailer, why should you check the trailer brakes are set?
- During uncoupling, when should you lower the landing gear?
- What should you do with the air lines and electrical cord before pulling the tractor away from the trailer during uncoupling?
- When uncoupling, what does pulling the fifth wheel release handle to the open position do?
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