Combination Flashcards
When backing a tractor under a trailer, you should:
a) Always use the lowest reverse gear
b) Always approach the trailer at a slight angle
c) Do it quickly to ensure that the kingpin is locked into the fifth wheel
a) Always use the lowest reverse gear
After the trailer has been coupled to the tractor, the tractor protection valve should be placed in what position?
a) Down
b) Up
c) Normal
c) Normal
The fifth wheel locking lever is not locked after the jaws have closed around the kingpin. This means that:
a) The trailer will not swivel on the fifth wheel
b) The parking lock is off, and you may drive away
c) The coupling is not right and should be fixed before driving the coupled unit
c) 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?
a) Tractor towing a 45 feet long trailer
b) Tractor with two 27 feet long trailers
c) 53 feet long bobtail
b) Tractor with two 27 feet long trailers
The air lines on combination vehicles are often colored to prevent them from getting mixed up. The emergency line is____ and the service line is____:
a) Red, blue
b) Black, yellow
c) Blue, red
a) Red, blue
Semi-trailers made before 1975 that are equipped with air brakes:
a) Usually need a glad hand converter
b) Often do not have spring brakes
c) Have only a service air line
b) 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:
a) 2
b) 3
c) 4
c) 4
Compared to a straight truck or bus there are ___ things to inspect on combination vehicles:
a) Fewer
b) The same amount
c) More
c) More
You have a major leak in the service line, and you put on the brakes. Service air pressure will escape and cause the:
a) Trailer emergency brakes to come on
b) Trailer tank pressure to be lost
c) Tractor spring brakes to lock up
a) Trailer emergency brakes to come on
A tractor with a ____ trailer will require the shortest amount of stopping distance:
a) Empty
b) Lightly loaded
c) Fully loaded
c) Fully loaded
When you get ready to back under a semitrailer, you should line up:
a) The kingpin to engage the driver’s side locking jaw first
b) Directly in front of the trailer
c) The left rear dual outer wheel with the kingpin
b) Directly in front of the trailer
To unlock the fifth wheel, the locking lever should be placed in the ____ position:
a) Neutral
b) Closed
c) Open
c) 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:
a) Service
b)Parking
c)Emergency
c)Emergency
When coupling, the proper position of the fifth wheel is:
a)Level with the ground
b)Tilted down toward the end of the trailer
c)Tilted up toward the end of the trailer
b)Tilted down toward the end of the trailer
What gear should the tractor be in after you uncouple the trailer and are inspecting the trailer supports?
a) Neutral
b) Low reverse
c) High reverse
a) Neutral
You have coupled to a semitrailer. Where should you put the iron trailer supports before driving away?
a) Raised half way with the crank handle secured in its bracket
b) Fully raised with the crank handle secured in its bracket
c) Three turns off the top with the crank handle secured in its bracket
b) Fully raised with the crank handle secured in its bracket
The safety catch for the fifth wheel locking lever must be ____ for coupling to be complete:
a) Over the locking lever
b) Under the locking lever
c) Straight up
a) 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:
a) Lifting the brake pedal
b) Watching your mirrors to see if the trailer lights come on
c) Applying and releasing the trailer brakes and listening for the sound of the brakes
c) Applying and releasing the trailer brakes and listening for the sound of the brakes
Before you back under a trailer, make sure that:
a)The trailer brakes are locked
b)The tractor protection valve is normal
c)The air supply knob is in
a)The trailer brakes are locked
When you are coupling a loaded trailer, you should lower the landing gear until it:
a) Makes firm contact with the ground, then turn the crank handle a few extra turns
b) Makes firm contact with the ground and lifts the trailer off the fifth wheel
c) Reaches the ground
a) Makes firm contact with the ground, then turn the crank handle a few extra turns
What will happen if the air lines are crossed when you hook up to an old trailer?
a) The hand valve will apply the tractor brakes instead of the trailer brakes
b) If the trailer has no spring brakes, you could drive away but you wouldn’t have trailer brakes
c) The brake lights will come on when the brake pedal is pressed
b) If the trailer has no spring brakes, you could drive away but you wouldn’t have trailer brakes
There are two things a driver can do to prevent a rollover. They are (1) keep the cargo as close to the ground as possible and (2):
a) Make sure that the brakes are properly adjusted
b) Keep both hands firmly on the steering wheel
c) Go slow around turns
c) Go slow around turns
To stop a trailer skid you should:
you are uncoupling a loaded trailer, you should lower the landing gear until it:
a) Use the trailer hand brake
b) Release the service brakes
c) Countersteer
b) Release the service brakes
Why should you be sure the fifth wheel plate is greased as required?
a) To ensure a good electrical connection
b) To prevent steering problems
c) To reduce heat and noise
b) To prevent steering problems
Your emergency air line breaks or gets pulled apart while driving. The loss of pressure will cause the:
a) Air compressor to unload instead of pumping air
b) Tractors air to dump into the trailer tank through the service line c) Emergency trailer brakes to come on
c) Emergency trailer brakes to come on
When connecting the glad hands, press the two coupler rubber seals together at what angle to each other?
a) 45 degrees
b) 90 degrees
c) 180 degrees
b) 90 degrees
Which of these statements is true?
a) The brakes and suspension system of combination vehicles work best with a light
load
b) Light vehicles need more braking power to stop than heavy ones
c) Bobtail tractors can take longer to stop than a combination vehicle loaded to maximum gross weight
c) Bobtail tractors can take longer to stop than a combination vehicle loaded to maximum gross weight
After you have coupled the trailer, you should start raising the landing gear by using:
a) Low gear
b) Intermediate
c) High gear
a) Low gear
You supply air to the trailer tanks by:
a) Pushing in the trailer air supply valve
b) Pulling out the trailer air supply valve
c) Connecting the service line glad hands
a) Pushing in the trailer air supply valve
Which part of the kingpin should the locking jaws close around?
a) The shank
b) The head
c) The base
a) The shank
How much space should be allowed between the upper and lower fifth wheel after coupling?
a) 1⁄4 inch
b) Just enough to sit on
c) Nothing
c) Nothing
You have pushed in the trailer air supply valve. You should not back a tractor under a trailer until the whole system is:
a) Empty
b) At normal pressure
c) Between 60 and 80 psi
b) At normal pressure
You are coupling a tractor to a semitrailer. You have connected the air lines. Before backing under the trailer, you should:
a) Supply air to the system then pull out the air supply knob
b) Pull ahead to test the glad hand connections
c) Make sure that the trailer brakes are off
a) Supply air to the system then pull out the air supply knob
The air brake leakage rate for a combination vehicle (engine off, brakes off) should be less than ___ psi per minute:
a) 1
b) 2
c) 3
c) 3
The safest way to make a turn without entering another traffic lane is to:
a) You should turn wide before you start the turn
b) You should turn wide as you complete the turn
c) You should not make the turn and find another place where you can turn without
crossing into another lane
b) You should turn wide as you complete the turn
The higher the center of gravity of your truck, the
a) Easier to turn around the corner
b) More stable the truck is while turning
c) Easier it is to turn over
c) Easier it is to turn over
The hand valve should be used:
a) Only with the foot brake
b) To test the trailer brakes
c) As a parking brake
b) To test the trailer brakes
When driving a set of doubles, it is necessary to close which shut- off valves on the last trailer?
a) Front
b) Middle section
c) Back
There are two things a driver can do to prevent a rollover. They are (1) go slow and (2):
a) Make sure that the brakes are properly adjusted
b) Keep both hands firmly on the steering wheel
c) Keep the cargo as close to the ground as possible
c) Keep the cargo as close to the ground as possible
If the service line comes apart while driving a combination vehicle, but the emergency line stays together, what will happen right away?
a) The trailers tank will exhaust through the open line
b) The emergency trailer brakes will come on
c) Nothing is likely to happen until you try to apply the brakes
c) Nothing is likely to happen until you try to apply the brakes
After connecting the air lines but before backing under the trailer you should:
a) Supply air to the system then pull out the air supply knob
b) Pull ahead to test the glad hand connections
c) Make sure that the trailer brakes are off
a) Supply air to the system then pull out the air supply knob
You are coupling a tractor to a semitrailer and have backed up but are not under it. What should you hook up before backing under?
a) The emergency and service air lines
b) The electrical service cable
c) Nothing. Back up and lock the fifth wheel
a) The emergency and service air lines
Why should you lock the tractor glad hands to each other or to a dummy coupler when you are not towing a trailer?
a) The connected brake circuit becomes a back-up air tank
b) It will keep dirt or water out of the lines
c) If you don’t, you could never build system pressure
b) It will keep dirt or water out of the lines
While driving behind another vehicle under good conditions you should allow at least one second between your vehicle and the vehicle ahead for each____ (how many) feet of your vehicle length?
a) 10
b) 20
c) 30
a) 10
Glad hands are usually connecting which of these:
a) Electric lines from the tractor to the trailer
b) Kingpin from the trailer to the locking jaws of the fifth wheel
c) Service and emergency air lines from the vehicle to the trailer
c) Service and emergency air lines from the vehicle to the trailer
You are about to back your tractor under a semitrailer. The trailer is at the right height when:
a) The kingpin is about 11⁄4 inches above the fifth wheel
b) End of the kingpin is even with the top of the fifth wheel
c) Trailer will be lifted slightly when the tractor backs under it
c) Trailer will be lifted slightly when the tractor backs under it
While checking if the trailer is securely coupled to the trailer, the landing gear should be:
a) Fully raised
b) Slightly raised
c) Fully lowered
b) Slightly raised
Air and electrical lines from the tractor to the trailer should be:
a) Fully tight
b) Secured, but with enough loop to turn
c) Resting on the frame of the tractor
b) Secured, but with enough loop to turn
After you lock the kingpin into the fifth wheel, you should check the connection by:
a) Pulling forward 50 feet while turning right and left
b) Backing up with the trailer brakes released
c) Pulling the tractor forward gently with the trailer brakes locked
c) Pulling the tractor forward gently with the trailer brakes locked
Where should the tractor be when you inspect the landing gear after uncoupling from the trailer?
a) With the tractor frame under the trailer
b) Completely cleared from the trailer
c) With the fifth wheel directly beneath the kingpin
a) With the tractor frame under the trailer
The front trailer supports are up, and the trailer is resting on the tractor. Make sure:
a) There is enough clearance between the top of the tractor tires and the nose of the
trailer
b) There is enough clearance between the tractor frame and the landing gear
c) Both a and b are correct
c) Both a and b are correct
When uncoupling the trailer, after you shut off the trailer air supply and lock the trailer brakes, you should:
a) Back up gently to ease pressure on the fifth wheel
b) Put on your tractor parking brakes
c) Lower the trailer landing gear
a) Back up gently to ease pressure on the fifth wheel
Air brake equipped trailers made before 1975:
a) Often do not have spring brakes
b) Usually need a glad hand converter
c) Cannot be legally operated on interstate highways
a) Often do not have spring brakes
The iron trailer supports are up and the trailer is resting on the tractor, be sure that:
a) There is enough clearance between upper and lower fifth wheels
b) The safety latch is in the unlocked position
c) There is enough clearance between the tractor frame and the landing gear
c) There is enough clearance between the tractor frame and the landing gear
When checking the trailer emergency brakes the tractor protection control valve should be placed in what condition?
a) Normal
b) Emergency
c) Neutral
b) Emergency
You are driving a combination vehicle when the trailer breaks apart, pulling apart both air lines. You expect the trailer brakes to come on and:
a) The trailer supply valve to stay open
b) The tractor to lose air pressure
c) The tractor protection valve to close
c) The tractor protection valve to close
In normal driving, some drivers use the land valve before the brake pedal to prevent a jackknife. Which of the statements is true?
a) It should not be done
b) It results in less skidding than using the brake pedal alone
c) It is the best way to brake and keep the truck in a straight line
a) It should not be done
When should you use the hand valve to park a combination vehicle?
a) To park at loading docks
b) To park on a grade
c) Never
c) Never
If the brakes are not released when you push the trailer air supply valve you should:
a) Check the air line connection
b) Cross the air lines
c) Check the electrical cable
a) Check the air line connection
How should you test the tractor-semitrailer connection for security?
a) Look at it carefully
b) Rock the trailer back and forth with the trailer brakes locked
c) Pull gently forward in low gear against the locked trailer brakes then look at it carefully
c) Pull gently forward in low gear against the locked trailer brakes then look at it carefully
