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Combination
| Question | Answer |
|---|---|
| Air lines on a combination vehicle are often colored to keep from getting them mixed up. The emergency line is: | Red |
| There are two things that a driver can do to prevent a rollover. They are: Keep the cargo as close to the ground as possible, and: | Reduce speed before entering turns |
| If the service line disconnects while you're driving, what will happen right away? | Nothing is likely to happen until you try the brakes |
| How do you supply air to the air tank on the trailer? | By pushing in the trailer air supply valve |
| With the engine off and the brakes released, a combination vehicle air brake system shouldn't leak more than how many psi in one minute? | 3 psi |
| You're hooking a tractor to a semi-trailer and have backed up but are not under it. What should you do before backing under the trailer? | Hook up the emergency and service air lines |
| The fifth wheel locking lever is not locked after the jaws close around the kingpin. This means that: | The coupling is not correct and should be corrected before driving the coupled unit |
| After pushing in the trailer supply valve, you should not move the tractor until the whole air system is: | At normal pressure |
| You cross the air lines when hooking up to an old trailer. What will happen? | If the trailer has no spring brakes, you could drive away but you wouldn't have trailer brakes |
| How far should you crank up the front trailer supports (dollies) after coupling a semi-trailer? | Fully raised with the crank handle secured |
| You're driving a combination vehicle when the trailer breaks away and pulls apart the air lines. You should expect the trailer brakes to apply and: | The tractor brakes to keep working properly |
| The hand valve should be used to park a combination vehicle: | Never |
| Air brake equipped trailers made before 1975: | Usually do not have spring brakes |
| In normal driving, some drivers use the trolley (hand) valve before the brake pedal in order to prevent trailer skids. Which of these statements is true? | It should never be done |
| When backing up under a trailer, you should line up: | Directly in front of the trailer |
| You're hooking up a tractor and semi-trailer, and you've connected both air lines. Before backing under the trailer, you should: | Supply air to the trailer system, then pull out the air supply knob to lock the trailer brakes |
| When not pulling a trailer, why is it a good idea to lock the glad hands together or to a dummy coupler? | It keeps dirt and water out of the lines |
| How much space should be between the upper and the lower fifth wheel plates? | None |
| After hooking up, you should check the fifth wheel connection by: | Pulling the tractor ahead gently with the trailer brakes locked |
| When should you use the hand valve to park a combination vehicle? | Never |
| You have coupled with a semi-trailer. Where should you put the front trailer supports before driving away? | Fully raised with the crank handle secured in its bracket. |
| You supply air to the trailer tanks by: | Pushing in the trailer air supply valve |
| 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. |
| 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. |
| In normal driving, some drivers use the hand valve before a brake pedal to prevent a jackknife. Which of these statements is true? | It should not be done |
| The air leakage rate for a combination vehicle (engine off, brakes off) should be less than ________ psi per minute. | 3. |
| The fifth wheel locking lever is 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. |
| Air lines on a combination vehicle are often colored to keep from getting them mixed up. The emergency line is _______; the service line is _______. | Red, Blue. |
| You are driving a combination vehicle when the trailer breaks away, pulling apart both air lines. You would expect the trailer brakes to come on and: | The tractor protection valve to close. |
| How much space should be between the upper and lower fifth wheel after coupling? | None |
| After you lock the kingpin into the fifth wheel, you should check the connection by: | Pulling the- tractor ahead gently with the trailer brakes locked. |
| The safety catch for the fifth wheel locking lever must be: | 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 brake sounds. |
| After connecting the air lines but before braking under the trailer, you should: | Walk around the rig to be sure that it is clear. |
| You should not back a tractor under a trailer until the whole air system is: | At normal pressure |
| Before you back under a trailer, make sure the: | Trailer brakes are locked. |
| 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. |
| You are coupling a semi-trailer to your tractor but we 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 |
| Here are two things that a driver can do to prevent a rollover. They are: (1) Go slow around turns; and (2): | Keep the cargo as close to the ground as possible. |
| Which part of the kingpin should the locking jaws close around? | The shank. |
| Which of these statements is true? | "Bobtail" tractors can take longer to stop than a combination vehicle loaded to maximum gross weight. |
| Your emergency air line breaks or gets pulled apart while you are driving. The loss of pressure will cause the: | Emergency trailer brakes come on. |
| Why should you be sure that the fifth wheel plate is greased as required? | To prevent steering problems. |
| What will happen if the air lines are crossed when you hook up to an old trailer? | If the trailer has no spring brakes, you could drive away but you would not have trailer brakes. |
| The front trailer supports are up and the trailer is resting on the tractor. Make sure: | There is enough clearance between the tops of the tractor tires and the nose of the trailer. |
| There is enough clearance between the tractor frame and the landing gear. | |
| Neither a or b is correct | |
| D.Both a and b are correct. | |
| 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. |
| Why should you lock the tractor glad hands to each other (or dummy couplers) when you are not towing a trailer? | It will keep dirt and water out of the lines. |
| The hand valve should be used: | To test the trailer brakes. |
| Semi-trailers made before 1975 that are equipped with air brakes. | Often do not have spring brakes. |
| When you get ready to back under a semi-trailer, you should line up: | Directly in front of the trailer. |
| The air leakage rate for a combination vehicle (engine off, brakes on) should be less than ______psi per minute. | 4. |
| You can prevent a roll over by keeping the cargo as close to the ground as possible and: | Going slow around curves. |
| Why are "bobtail" tractors harder to stop? | The vehicle is lighter |
| On a combination vehicle, to stop a jackknife: | Do not use the trailer hand brake. |
| Offtracking is: | When the rear wheels follow a different path than the front wheels. |
| You need ________ times more stopping distance when stopping a combination at 40 miles per hour than at 20 miles per hour. | Four times. |
| The trailer air supply: | Supplies the trailer with air. |
| The service air line: | Carries air to the trailer brakes. |
| What color are the emergency line couplers? | Red. |
| Why should you connect the air hose couplers together? | To keep the dirt and water out of the lines. |
| What happens when you cross the air lines of an older trailer without spring brakes? | You could drive away, but have no trailer brakes. |
| Why do many trailers built before 1975 have no parking brakes? | They don't have spring brakes. |
| If the service air line comes apart while driving but the emergency line is okay, what happens immediately? | Nothing is likely to happen until you press the brakes. |
| You should always grease the fifth wheel because: | It prevents steering problems. |
| What should you do just before the tractor is coupled? | Connect the emergency and service air lines |
| In coupling, where should the tractor be lined up: | Directly in front of the trailer |
| In coupling, the trailer is at the right height when: | The trailer is lifted slightly when the tractor connects. |
| During coupling, how do you lock the trailer brakes before you back under the trailer? | Pull out the air supply knob. |
| To make sure the kingpin and fifth wheel connection are secure, what should you do? | Slowly drive forward with the trailer brakes locked. |
| When coupling is complete, how much space should there be between the upper and lower fifth wheel? | No space. |
| When the fifth wheel locking lever is almost in the locking position but will not lock, what should you do? | Have it repaired before driving. |
| After the tractor is coupled, you should not move it until you push in the air supply knob and: | Wait until the air pressure is normal. |
| After coupling, you can make sure the air lines are not crossed because: | When you pump the brake you will hear the brakes move and air escape. |
| When the engine and brake are off, the air leakage rate for combination vehicles must be less than: | 3 psi per minute. |
| The maximum leakage rate for a combination vehicle with the engine off and brakes on is: | 4 psi per minute. |
| You should use the trailer hand valve: | To test the trailer brakes. |
| Why do you need a tractor protection valve? | It keeps air in the tractor if the trailer breaks away or develops a bad leak. |
| The tractor protection valve will close automatically when: | The air pressure is low (20 to 45 psi). |
| When testing the trailer emergency brakes, you should charge the air brake system, check that the trailer rolls freely, and: | Pull out the trailer air supply control. |
| After you have turned the hand brake on, how do you check the trailer brakes? | Bring the air pressure up to normal. |
| Turn the parking brakes off. | |
| Move slowly forward to see if the vehicle slows down. | |
| D.All of the above. |
Created by:
kevin18st