combination Flashcards
You should not back a tractor under a trailer until the whole air system is
At normal pressure
You are coupling a semi trailer to your tractor but have not yet backed under. The trailer is at the right height when
It will be raised slightly when the tractor is backed under it
Which part of the kingpin should the locking jaws close around?
The shank
When you get ready to back under the semi trailer you should line up
Directly in front of the trailer
How should you test the tractor semi trailer connection for security?
Pull gently forward in low gear against the locked trailer brakes, then look at it carefully
When should you use the hand valve to park a combination vehicle?
Never
You supply air to the trailer tanks by
Pushing in the trailer air supply valve
Why should you be sure that the fifth wheel plate is greased as required?
To prevent steering problems
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
Applying and releasing the trailer brakes and listening for brake sounds
There are two things that a driver can do to prevent a roll over. They are: (1) Keep the cargo as close to the ground as possible; and (2)
Go slowly around turns
Before you back under a trailer, make sure the
Trailer brakes are locked
If the service air line comes apart while you are driving a combination vehicle but the emergency line stays together, what will happen right away?
Nothing is likely to happen until you try to apply the brakes
The air leakage rate for a combination vehicle (engine off, brakes on) should not Be more than ____ psi per minute
4
In normal driving, some drivers use the hand valve before applying the brake pedal to prevent a jackknife. Which of these statements is true?
It should not be done.
The driver crosses the air lines when hooking up to an old trailer. What will happen?
If the trailer has no spring brakes, you can drive away, but you will not have trailer brakes
Why should you lock the tractor glad hands (or dummy couplers) to each other when you are not towing a trailer?
It will keep dirt and water out of the lines
The safety catch for the fifth wheel locking lever must be ____ for a coupling to be complete
Over the locking lever
The front trailer supports are up and the trailer is resting on the tractor. Make sure
a. There is enough clearance between the tractor frame and the landing gear.
b. There is enough clearance between the tops of the tractor tires and the nose of the trailer.
You have a major leak in the service line and you put on the brakes. Service air pressure will escape and cause the:
Trailer emergency brakes to come on
When backing under a tractor under a trailer you should expect
Trailer will be lifted slightly when the tractor backs under it
You are coupling a tractor to a semi trailer and have backed up but are not under it. What should you hook up before backing under?
The emergency and service air lines
You have coupled with a semi trailer. In what position should you put the front trailer supports before driving away?
Fully raised with the crank handle secured in its bracket
Air lines on a combination vehicle are often colored to keep them from getting mixed up. The emergency line is ____; the service line is ____.
Red, blue
Which of these statements is true?
“bobtail” tractors can take longer to stop than a combination vehicle loaded to the maximum gross weight
