Combination Flashcards
When should you use the hand valve to park a combination vehicle?
a. Never
b. To park at loading docks
c. To park on a grade
Never
Semitrailers made before 1975 that are equipped with air brakes:
a. often they don’t have spring brakes
b. usually need glad hand converter
c. they have only one air service line
often they don’t have spring brakes
The hand valve should be used:
a. only with the foot brake
b. to test the air brakes
c. like a parking brake
to test the air brakes
The best way to verify whether your truck has started to skid is by:
a. feel a pull in the cab
b. looking through your mirrors
c. hear the wheels skid
looking through your mirrors
How much space should be between the upper and lower fifth wheel after coupling?
a. approximately 1/4 of an inch
b. just enough to see light through it
c. none
none
Air and electric tractor lines should be:
a. firmly pulled, with very little loose parts
b. over the tractor structure
c. secured in place, but make sure it will be loose enough when it makes turns
secured in place, but make sure it will be loose enough when it makes turns
When unlock the fifth wheel, pull the release handle to:
a. close position
b. neutral position
c. open position
open position
You have coupled with a semitrailer. In what position should you put the front trailer supports before driving away?
a. raised (1/2) way with the crank handle secured in its bracket
b. raised 3/4 with the crank handle removed
c. fully raised with the crank handle secured in its bracket
fully raised with the crank handle secured in its bracket
You are coupling a tractor and semitrailer, and have connected the air lines. Before backing under the trailer, you should:
a. make are that the trailer brakes are off
b. supply air to the trailer system, then pull out the air supply knob to lock the trailer brakes
c. move forward to test the glad hands
supply air to the trailer system, then pull out the air supply knob to lock the trailer brakes
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 electrical service cable
b. nothing: back up and lock the fifth wheel
c. the emergency and service air lines
the emergency and service air lines
In general, the higher the gravity center of your truck the:
a. easier to make a turn at the corner
b. easier to rollover
c. more stable when you take a turn
easier to rollover
When you driving a set of doubles, it’s necessary to:
a. shut off valve at front of the last trailer
b. shut off valve in the middle of the last trailer
c. shut off valve at the rear of the last trailer
shut off valve at the rear of the last trailer
If the air lines cross over when hooking up to an old trailer, what will happen?
a. if the trailer has no spring brakes, you can drive away, but you would not have trailer brakes
b. the hand valve will apply the tractor brakes instead of the trailer brakes
c. the brake lights won’t turn on, when you put on the brake pedal
if the trailer has no spring brakes, you can drive away, but you would not have trailer brakes
Which of these statements is true?
a. the brake systems and the combination vehicle suspension will work better with a light weight
b. light vehicles need more braking power to stop than heavy ones
c. Bobtail tractors can take longer to stop than combination vehicles loaded to the maximum gross weight
Bobtail tractors can take longer to stop than combination vehicles loaded to the maximum gross weight
When you lock the kingpin to the fifth wheel, you should check the couple by
a. pulling the tractor forward, slightly with the trailer brakes on
b. pulling the tractor forward, a sharpness way to release the trailer brake
c. pulling forward 50 feet, then turning right and left
pulling the tractor forward, slightly with the trailer brakes on
You have pushed the trailer supply valve. you should not move a tractor until the whole air system is:
a. at normal pressure
b. between 60 and 80 psi
c. empty
at normal pressure
When you uncouple a trailer, after turning off the trailer air supply and putting on the trailer brakes, you should:
a. start down the trailer landing gear
b. back slowly, to decrease the pressure from the locking jaws of the fifth wheel
c. immediately put on the tractor parking brakes
immediately put on the tractor parking brakes
You supply air to the trailer tanks by:
a. connecting the service line glad hand
b. pushing in the trailer air supply valve
c. pulling out the trailer air supply valve
pushing in the trailer air supply valve
You are about to back your tractor under a semitrailer, the trailer is at the right height when the:
a. the kingpin is 1 & 1/4 over the fifth wheel
b. trailer will be lifted slightly when the tractor backs under it
c. end of the kingpin is even with top of the fifth wheel
trailer will be lifted slightly when the tractor backs under it
You should not back a tractor under a trailer until the whole air system is:
a. at normal pressure
b. between 60 psi and 80 psi
c. empty
at normal pressure
A tractor trailer combination has more probability to roll over on a curve, when the configuration includes:
a. a 45 feet trailer long and one 27 feet long
b. double trailers 45 feet long
c. triple trailers 27 feet long
triple trailers 27 feet long
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:
a. the trailer supply valve to stay open
b. the tractor protection valve to close
c. the tractor to lose all air pressure
the tractor protection valve to close
The tractor protection valve will close and the trailer emergency brakes will apply when there is a big leak in:
a. service brake line
b. parking brake line
c. emergency brake line
emergency brake line
If the spring brakes don’t release when you put on the trailer air supply control, you should:
a. cross the air lines
b. check air line connections
c. check the electric service cable
check air line connections
Why should you be sure that the fifth wheel plate is greased as required?
a. to prevent steering problems
b. to ensure good electrical connections
c. to reduce heat and noise
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:
a. applying and releasing the trailer brakes, and listening for brake sounds
b. watch your mirrors to see if the trailer lights are turning on
c. turning on the parking brakes from the cab
applying and releasing the trailer brakes, and listening for brake sounds