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Combination Vehicles
CDL
Question | Answer |
---|---|
When backing a tractor under a trailer you should ___________. | Always use the lowest reverse gear. |
After the trailer has been coupled to the tractor, the tractor protection control valve should be placed in what posistion? | Normal position. |
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. |
Off-tracking or cheating causes which of these to follow the wider pass while making a turn? | Tractor towing a 45-feet trailer. |
The air lines on combination vehicles are often colored to prevent them from mixing up. The emergency line is _________ and the service line is ________. | Red, Blue |
The semitrailer made before 1975 that are equipped with air brakes: | Often do not have spring brakes. |
The air leakage rate for a combination vehicle (engine off, brakes on) should be less than _______ psi per minute. | 3 |
You have a major leak in the service line and you put on the brakes. Service air will escape and cause the: | Trailer emergency brakes to come on. |
A tractor with a _______ trailer requires the shortest amount of stopping distance? | Fully loaded |
When you get ready to back under a semitrailer you should line up: | Directly in front of the trailer. |
To unlock the fifth wheel the locking lever should be placed in the ________ position. | Open |
The tractor protection valve will close and the trailer emergency brakes will come on when there is a major leak in the _______ brake line. | Emergency |
When coupling, the proper position of the fifth wheel is: | Tilted down toward the end of the trailer. |
What gear should the tractor engine be in after you uncouple the trailer and are inspecting the trailer supports? | Neutral |
You have coupled with a semitrailer. Where should you put the iron trailer supports before driving away? | Fully raised with the crank handle secured in its bracket. |
The safety catch for the fifth wheel locking lever must be _________ for the couplimg to be complete. | Over the locking lever. |
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 the sound of the brake. |
Before you back under a trailer, make sure that: | The trailer brakes are locked. |
When you are uncoupling a loaded trailer you should lower the landing gear until it: | Make firm contact with the ground, then crackle hits a low gear a few extra turns. |
What will happen if the air lines are crossed when you hook up an old trailer? | If the trailer has no spring brakes, you could drive away but you wouldn't have trailer brakes. |
There are two things you can do to prevent a rollover. They are (1) keep the cargo as close to the ground as possible, and (2): | Go slow around turns. |
To stop a trailer skid, you should: | Release the service brakes. |
Why should you be sure that the fifth wheel plate is greased as required? | To prevent steering problems. |
Your emergency air line breaks or gets pulled apart while you are driving. The loss of pressure will cause the: | Emergency trailer brakes to come on. |
When connecting the glad hands, press the coupler together at what degree to each other? | 90 degrees. |
Which of these statements is true? | Bobtail tractors can take longer to stop than a combination vehicle loaded to maximum gross weight. |
Tractor with _______ trailer requires the shortest amount of stopping distance? | Fully loaded. |
After you have coupled the trailer you should have to raise the landing gear by using: | Low gear. |
You supply air to the trailer tanks by: | Pushing in the trailer air supply valve. |
Which part of the kingpin should the locking jaws close first? | The shank. |
How much space should be allowed between upper and lower fifth wheel after coupling? | Nothing. |
You have pushed the trailer air supply valve. You should not back a tractor under a trailer until the whole air system is: | At normal pressure. |
You are coupling a tractor to a semitrailer. You have connected the air lines. Before backing under the trailer you should: | Supply air to the trailer system, then pull out the air supply knob. |
The air leakage rate for a combination vehicle (engine off, brakes off) should be less than _______psi per minute. | 3 |
The safest way to make turns without entering another traffic lane is: | You should turn wide as you complete the turn. |
The higher the center of gravity of your truck, the: | Easier to turn over. |
The hand valve should be used: | To test the trailer brakes. |
When driving a set of doubles, it is necessary to close which shut-off valve in the last trailer? | Back valve. |
If the service 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. |