22. 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:

a. lifting the brake pedal.
b. turning on the parking brakes from the cab.
c. watching your mirrors to see if the trailer lights come on.
d. applying and releasing the trailer brakes and listening for brake sounds.

23, After connecting the air lines but before backing under the trailer you should:

a. pull ahead to test the glad hand connections.
b. supply air to the trailer system then pull out the air supply knob.
c. make sure that the trailer brakes are off.
d. walk around the rig to be sure that it is clear.

24. You should not back a tractor under a trailer until the whole air system is:

a. empty.
b. at normal pressure.
c. bled down to half the minimum pressure.
d. between 60 and 80 psi.

25. Before you back under a trailer make sure the:

a. trailer brakes are locked.
b. tractor protection valve is normal.
c. air brakes are off.
d. air supply knob is in.

26. How should you test the tractor-semi-trailer connection for security?

a. Look at it carefully.
b. Rock the trailer back and forth with the trailer brakes locked.
c. Put the tractor in gear and pull ahead with a sharp jerk.
d. Pull gently forward in low gear against the locked trailer brakes then look at it carefully.

27. There are two things that a driver can do to prevent a rollover. They are: (1) Go slow around turns and (2):

a. Make sure that the brakes are properly balanced.
b. Keep both hands firmly on the steering wheel.
c. Keep the cargo as close to the ground as possible.
d. Keep the fifth wheel free play as small as possible.

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

a. The shank.
b. The head.
c. The base.
d. It does not matter.

Answers: (22)d   (23)b   (24)b   (25)a   (26)d   (27)c   (28)a