08. The air leakage rate for a combination vehicle (engine off, brakes off) should be less than ___ psi per minute.

a. 1/2
b. 1
c. 2
d. 3

09. When you get ready to back under a semi-trailer you should line up:

a. about 1/2 degrees off the line of the trailer.
b. the kingpin to engage the driver's side locking jaw first.
c. directly in front of the trailer.
d. the left rear outer dual wheel with the kingpin.

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

a. the trailer will not swivel on the fifth wheel.
b. you can set the fifth wheel for weight balance.
c. the parking lock is off and you may drive away.
d. the coupling is not right and should be fixed before driving the coupled unit.

11. There are two things that a driver can do to prevent a rollover. They are: (1) Keep the cargo as close to the ground as possible (2):

a. Me sure that the brakes e properly adjusted.
b. Keep both hands firmly on the steering wheel.
c. Go slow around turns.
d. Keep the fifth wheel free play tight.

12. Air brake equipped trailers made before 1975:

a. often do not have spring brakes.
b. are easier to brake than newer trailers because they are heavier.
c. usually need a glad hand converter.
d. cannot be legally operated on interstate highways.

13. You have pushed in the trailer supply valve. You should not move the tractor until the whole air system is:

a. empty.
b. at normal pressure.
c. flushed of all moisture.
d. between 60 and 80 psi.

14. You are coupling a tractor and a semi-trailer and have connected the air lines. 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 to lock the trailer brakes.
c. make sure that the trailer brakes are off.
d. apply the brakes twice to alert others.

Answers: (8)d   (9)c   (10)d   (11)c   (12)a   (13)b   (14)b