Coupling & UncouplingQuestion 9 of 60
Before supplying air to the trailer, why should you check the trailer brakes are set?
a.To keep the trailer from moving when the tractor backs under it or when air is applied
b.To warm up the brake shoes
c.To test the ABS light
d.To release the parking brake automatically
Explanation
You should ensure the trailer brakes are locked, either with wheel chocks or by having air already in the system, so the trailer cannot move while coupling. A trailer that rolls during coupling can cause serious injury or damage. Chock the wheels if you are not sure the spring brakes will hold.
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Related questions on this topic
- After the tug test, why should you go under the trailer and look into the back of the fifth wheel?
- 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?
- When you push the trailer air supply valve in (supply air to trailer), what should happen?
- 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?
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