COMBINATION VEHICLES

Question 1

You supply air in the tanks by

Answer 1

pushing in the trailer air supply valve

Question 2

Loss of air pressure in the emergency line causes

Answer 2

the trailer’s emergency brakes to come on

Question 3

A tractor with a _ trailer requires the shortest amount of stopping distance

Answer 3

fully loaded

Question 4

Which of these statements is true?

Answer 4

bobtails tractors can take longer to stop than fully loaded combination vehicles

Question 5

If you cannot make a right turn without swinging into another lane, you should:

Answer 5

turn wide as you complete the turn

Question 6

The tractor protection valve will close and the trailer emergency brakes will
come on when there is a major leak in what air line?

Answer 6

emergency

Question 7

Off tracking or “cheating” causes which of these to follow the widest path while making a turn?

Answer 7

3 axle tractor towing a 45 ft trailer

Question 8

If your vehicle gets stuck on a railroad crossing, you should:

Answer 8

get out of the vehicle and away from the tracks

Question 9

When driving a set of double trailers, it is necessary to close shut-off valves
on some trailers. Where are these valves located?

Answer 9

at the back of trailers used to tow other trailers

Question 10

Before you back under a trailer, make sure of what?

Answer 10

the trailer brakes are locked

Question 11

To unlock the fifth wheel, you pull the handle to what position?

Answer 11

open

Question 12

After connecting the air lines but before backing under the trailer, you
should:

Answer 12

supply air to the trailer, then pull out the trailer air supply valve

Question 13

You are coupling a tractor to a semi-trailer and you have backed up but are not yet under it. What should you hook up before backing under it?

Answer 13

the emergency and service air lines

Question 14

You are coupling a tractor to a trailer. The trailer is at the right height when:

Answer 14

the trailer is raised slightly when the tractor is backed under it

Question 15

Why should you connect the air lines to a dummy coupler when they are not in use?

Answer 15

it will keep dirt and water out of the lines

Question 16

The air leakage rate for a combination vehicle with the ENGINE OFF and the
BRAKES OFF should be less than _ per minute.

Answer 16

3 psi

Question 17

Air and electric lines from the tractor to the trailer should be:

Answer 17

secured properly with enough slack for turns

Question 18

Air brake equipped trailers made before 1975

Answer 18

often do not have spring brakes

Question 19

The hand valve should be used

Answer 19

to test the trailer brakes

Question 20

The air leakage rate for a combination vehicle with the ENGINE OFF and the
BRAKES ON should be less than__ per minute.

Answer 20

4 psi

Question 21

Your emergency line breaks or gets pulled apart while driving. The loss of
pressure will cause the:

Answer 21

emergency trailer brakes to come on

Question 22

You have pushed in the trailer air supply valve. You should not move the
vehicle until the whole system is:

Answer 22

at normal pressure

Question 23

When should you use the hand valve to park a combination vehicle?

Answer 23

never

Question 24

The best way to tell that your trailer has started to skid is to:

Answer 24

see it in your mirrors

Question 25

A trailer is most likely to jackknife when it is:

Answer 25

empty

Question 26

If the service line comes apart but the emergency line stays together, what will happen right away?

Answer 26

nothing is likely to happen until you try to apply the brakes

Question 27

When backing a tractor under a trailer you should:

Answer 27

always use lowest reverse gear

Question 28

After you have coupled the trailer, you should begin raising the landing gear using what gear?

Answer 28

low gear

Question 29

You will know the trailer you are using has ABS by:

Answer 29

a yellow malfunction lamp on the left side

Question 30

If you cross the air lines while coupling to an old trailer what will happen?

Answer 30

if the trailer has no spring brakes, you could drive away but you would not have trailer brakes

Question 31

When should you get out of your vehicle when you are backing a trailer?

Answer 31

when you are unsure of your path of travel

Question 32

When you are uncoupling a loaded trailer, you should lower the landing gear until it:

Answer 32

makes firm contact with the ground, then turn it a few extra cranks in low gear

Question 33

How much space should be between the upper and lower fifth wheel after coupling?

Answer 33

none

Question 34

The front trailer supports are up and the trailer is resting on the tractor. Make sure:

Answer 34

there is enough clearance between the frame and the landing gear

Question 35

Why should you be sure that the fifth wheel is greased as required?

Answer 35

to prevent steering problems

Question 36

After you lock the kingpin into the fifth wheel, you check the connection by:

Answer 36

pulling the tractor ahead gently with trailer brakes locked

Question 37

After you supply air to the trailer, make sure the lines are not crossed and the brakes are working. This is done by:

Answer 37

applying and releasing the trailer brakes and listening for sounds

Question 38

you should maintain at least one second of distance for each _ of vehicle length as following distance.

Answer 38

10 ft

Question 39

Two things you can do to prevent rolling over are keep the cargo as low to the ground as possible, and:

Answer 39

go slow around turns

Question 40

You have a major leak in the service line and you put on the brakes. Service air pressure will escape and if it goes low enough will cause the:

Answer 40

trailer emergency brakes to come on

Question 41

When uncoupling a trailer, after you have locked the trailer brakes, you should:

Answer 41

back up gently to ease pressure on the fifth wheel jaws

Question 42

When do you need to use chocks to park a trailer that does not have spring brakes?

Answer 42

always

Question 43

The fifth wheel locking lever is not locked after the jaws close around the kingpin, this means:

Answer 43

the coupling is not right and should be fixed before driving

Question 44

When you get ready to back under a trailer, you should line up:

Answer 44

directly in front of the trailer

Question 45

After you have coupled to a trailer, the tractor protection valve should be placed in the _ position.

Answer 45

normal

Question 46

How should you test the trailer connection for security?

Answer 46

pull gently forward with the trailer brakes locked, then look at it carefully

Question 47

The trailer air supply valve should automatically close when air pressure falls to what range?

Answer 47

20-45 psi

Question 48

What part of the kingpin should the jaws be locked around?

Answer 48

the shank

Question 49

The higher your center of gravity of your truck, the:

Answer 49

easier it is to turn over

Question 50

When checking that the trailer is securely coupled to the tractor, the landing gear should be:

Answer 50

slightly raised

Question 51

If you must back your trailer on a curved path, you should position your vehicle so you can back

Answer 51

to the drivers side

Question 52

If your ABS is not working on your trailer, you should

Answer 52

drive normally but get the system serviced soon

Question 53

Compared to a straight truck or bus, there are _ things to inspect on a combination vehicle.

Answer 53

more

Question 54

Air lines are often colored. The emergency line is? The service line is?

Answer 54

red(emergency) blue(service)

Question 55

To stop a trailer skid you should

Answer 55

release service brake

Question 56

What gear should the transmission be in after you have uncoupled and are inspecting the trailer supports?

Answer 56

neutral

Question 57

You have coupled to a trailer. Where should the landing gear be before driving away?

Answer 57

fully raised with the crank handle secure in the bracket