Combinations Practice Test

Front

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

Back

Release the service brakes.

Front

After you lock the kingpin into the fifth wheel, you should check the connection by:

Back

Pulling the tractor ahead gently with the trailer brakes locked.

Front

Before backing under the trailer after connecting the air lines, what should you do?

Back

Supply air to the trailer system, then pull out the air supply knob to lock the trailer brakes.

Front

In general, the higher the "center of gravity" of your truck, the:

Back

Easier it is to turn over.

Front

How to identify if a trailer has antilock brakes?

Back

Yellow ABS malfunction lamps on the left side of the trailer.

Front

Loss of air pressure in the emergency line causes:

Back

The trailer's emergency brakes to come on.

Front

When coupling, the proper position of the fifth wheel is:

Back

Tilted down towards the end of the tractor.

Front

If you must back your trailer on a curved path, you should try to position your vehicle so you can back:

Back

To the driver’s side

Front

To unlock the fifth wheel, pull the release handle to the ____ position.

Back

Open

Front

When uncoupling a trailer, after you have shut off the trailer air supply and locked the trailer brakes, you should:

Back

Back up gently to ease pressure on the fifth wheel locking jaws.