Combination Vehicle Practice Test

Question 1

The fifth wheel locking lever is not locked after the jaws have closed around the kingpin. This means that:

Answer 1

The coupling is not right and should be fixed before driving the coupled unit

Question 2

Semi trailers made before 1975 that are equipped with air brakes:

Answer 2

Often do not have spring brakes

Question 3

The air leakage rate for a combination vehicle(engine off, brakes on) should be less than____psi per minute:

Answer 3

4

Question 4

The safety catch for the fifth wheel locking lever must be ____ for coupling to be complete

Answer 4

Over the locking lever

Question 5

After you supply air to the trailer, make sure the air lines are not crossed and the trailer brakes are working. This is done by:

Answer 5

Applying and releasing the trailer brakes and listening for the sound of the brakes

Question 6

When you are uncoupling a loaded trailer, you should lower the landing gear until it:

Answer 6

Makes firm contact with the ground, then turn the crank handle a few extra turns

Question 7

You supply air to the trailer tanks by:

Answer 7

Pushing in the trailer air supply valve

Question 8

Which part of the kingpin should the locking jaws close around?

Answer 8

The shank

Question 9

You have pushed in the trailer air supply valve. You should not back a tractor under a trailer until the whole system is:

Answer 9

At normal pressure

Question 10

Where should the tractor be when you inspect the landing gear after uncoupling from the trailer?

Answer 10

With the tractor frame under the trailer

Question 11

When checking the trailer emergency brakes the tractor protection valve should be placed in what position?

Answer 11

Emergency