Combination 6

If you’re glad hands on your tractor are not color-coded, how can you determine which one is the emergency line?

• Hook them up and hope for the best.

• Push in your trailer supply knob and listen for the sound of air escaping from the glad hand to find out which one is the emergency line.

• Hook them both up, release the brakes, drive forward fast, and slam on the brakes.

• There is no way to tell which is which if they are not color-coded.

In normal driving, some drivers apply the hand valve before using the brake pedal to prevent a jack knife. Which of these statements is true?

• It should not be done

• It results in less skidding than using the brake pedal alone

• It is the best way to brake and keep the truck in a straight line

• It should only be done on wet surfaces

In order to inspect a coupling you should:

• Make sure there is plenty of space between the upper and lower fifth wheel (apron and fifth wheel)

• Check that the release arm is out

• Make sure the fifth will jaws are open

• Use a flashlight if necessary

In order to supply air to the trailer, you must first

• Push in the tractor protection valve

• Pull out the trailer air supply

• Stop the engine so you can hear the brakes

• Cross the airline so that you can check for leaks

It takes tractors without trailers longer to stop than tractor trailer combinations loaded a maximum gross weight.

• True

• False

More than half of truck driver deaths are due to rollovers.

• True

• False

Which of the following vehicles off-track (cheating) the most?

• Tractor towing a 45-foot trailer

• Bobtail tractor

• City bus

• Tractor with two 27 foot trailers

One reason for driving slowly around corners when loaded is:

• To prevent rollovers

• To prevent blowouts

• To prevent overheating

• To prevent over acceleration

Shut-off valves can be found at the front and back of the trailers.

• True

• False

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

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

• The parking lot is off and you may drive away

• The trailer will not swivel on the fifth wheel

• This can be fixed by swinging wide to the left and right