Combination 4

To stop a trailer skid, you should

• Use the trailer hand brakes

• Release the brakes

• Countersteer

While you check if the rear trailer is securely coupled to the front trailer, the landing gear should be

• Fully raised.

• Slightly raised.

• Fully lowered.

The fifth wheel locking lever is not locked after the Jaws close around the king pin. This means that

• The parking lock is off and you may drive away.

• The trailer will not swivel on the fifth wheel.

• The coupling is not right and should be fixed before you drive the coupled unit.

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

• The shank

• The head

• The bass

The kingpin is located into the fifth wheel, the front trailer supports are up, and the trailer is resting on the fifth wheel. Make sure that

• There is enough clearance between the tractor frame and the landing gear to accommodate sharp turns.

• The safety latch is in the unlocked position.

• There is enough clearance between the upper and lower fifth wheel (apron and fifth wheel).

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

• Put the tractor in gear and pull ahead with a sharp jerk.

• Pull gently forward in low gear against the locked trailer brakes; then look at it carefully.

• Rock the trailer back-and-forth with the trailer brakes locked.

Glad hands are used to connect the

• Service and emergency air lines from the truck or tractor to the trailer.

• Electrical lines from the tractor to the trailer.

• Kingpin from the trailer to the locking jaws of the fifth wheel.

When coupling, the proper position of the fifth wheel is

• Tilted down toward the rear of the tractor.

• Level with the ground.

• Tilt it up toward the rear of the tractor.

You cross the air lines when hooking up to an old trailer. What will happen?

• The hand valve apply the tractor brakes instead of the trailer brakes.

• If the trailer has no spring brakes, you will be able to drive away but you won’t have trailer brakes.

• The brake lights will come on when the brake pedal is pressed.

The tractor protection valve will close and the trailer spring brakes will come on when there is a major leak in the _______ line.

• Parking

• Service

• Emergency