The tractor protection valve closes automatically when the air pressure is too low.

• True
• False

The trailer air supply control . . .

a.operates the tractor protection valve, and in the event of a rapid air loss, will cause the emergency brakes on a trailer to be applied.

b. is a red 8-sided knob on new vehicles.

c. shuts off air to the trailer if air pressure drops to the 20 - 40 p.s.i. range.

d. all of the above.  

The tractor protection valve keeps air in the tractor if the trailer breaks away.

a. True

b. False

The rear wheels of the trailer will off-track the most.

a. True

b. False

The emergency airline is . . .

a. also called the supply line, which supplies air to the trailer air tanks and controls the trailer emergency brakes.

b. must be connected directly to the air horn.

c. a red 8-sided push-pull knob.

d. used only in emergency situations. 

The fifth wheel walking lever is not locked after the jaws close around the kingpin. This means 

• that you are ready to connect the electrical cord and check the airlines.
• That the fifth wheel locking lever is not bonding, allowing safe travel.
• The coupling is complete
• the coupling isn't right, don't drive the coupled unit, until fixed

The service airline…

• Is used to keep tire pressure within specifications
• is operated by the brakes pedal and trailer and valve
• is also called the supply line
• cannot be called a control line or single-line

The trailer must remain perfectly level when the tractor is backed under it.

• True
• False

The tractor emergency airline should be connected to the trailer emergency glad hand

• true
• False

Two things can help keep you from rolling your vehicle, they are

• increase speed before you turn and load cargo to the driver side
• drive slowly around turns and keep cargo as close to the ground as possible
• drive slowly around turns and keep cargo near the door
• accomplish lane changes as quickly as possible

To test for crossed airlines,

• pull the red, eight-sided knob and wait for air pressure to build up to normal
• pull ahead 10 feet and  brake slowly
• turn the engine off, apply and release the brake pedal and look for an air pressure drop
• turn the engine off, apply and release the trailer brakes with the hand valve, and listen for brake movement and air release, check system pressure gauge for major air loss

When testing the tractor protection valve, the belt should close automatically when the air pressure is reduced to

• zero
• Gov. low-limit pressure
• 20 to 45 PSI
• 60 PSI

When not pulling a trailer, why is it a good idea to lock the glad hand together or to dummy couplers

• to keep the seals from falling out
• to keep air from leaking out of the system
• to keep dirt and water out of the lines
• none of the above

When hooking a tractor to a trailer, the trailer should be

• low enough that it is raised slightly by the tractor when you backed the tractor under it
• at an angle to the tractor, never directly behind& high enough that it is not raised by the tractor when you back the tractor under it
• low enough that the tractor will strike the nose of the trailer

When testing the  brake system for a combination vehicle, you should not hear air escaping when you open the emergency line shut off valve

• True
• False

When coupling to the trailer, the field will

• be properly lubricated
• be tilted down towards the rear of the tractor
• unlocking handle in the automatic lock position
• all of the above

When backing up under a trailer, you should line up…

• About 15° off the line of the trailer
• the right mirror along the right edge of the trailer
• directly in front of the trailer

When pulling doubles, which unit is more likely to turn over?

• Lead trailer
• boat trailers equally
• rear trailer
• the tractor

When cranking up the landing gear, which statement is true

• landing gears should be cranked up just enough to clear the ground
• landing gear should be cranked up as high as they will go in cranked hand secured
• landing gear should be cranked up as high as they will go
• landing gears are stationary. The trailer is cranked up or down

Rearward amplification

• is lower for each unit added
• is higher for each unit added
• prevents rollover
• prevents fish-tailing

When the wheels of a trailer lockup, the trailer tends to swing around. This is called

• fish-tail
• trailer jackknife
• trailer off tracking
• tractor trailering

Which of the following statements is true?

• It takes longer to stop a loaded vehicle
• it takes longer to stop an eight the vehicle
• it takes the same amount of time to stop a loaded vehicle as it does to stop an empty vehicle

The trailer hand valve

• should be used to stop the trailer
• lowers and raises the landing gear
• should never be used for braking when driving
• should only be used for braking when drivingFalse

With the engine off in the brakes released, a combination vehicle air brake system should not leak more than how many psi in one minute

• 1
• 2
• 3
• 4

You are cooking up a tractor and semi-trailer. You have connected both airlines. Before backing under the trailer you should

• make sure there is no space between the upper and lower fifth wheel
• supply air to the trailer system, then pull out the air supply not to lock the trailer brakes
• make sure that the trailer brakes are off
• turn it approximately a team degree angle to the trailer

You should never use the trailer hand valve for parking

• true
• False

The supply air to the air tank on the trailer by

• pushing in the trailer air supply valve
• pulling out the trailer air supply valve
• activating the service line
• apply the trolley valve

You should swing wide to the left before starting a right turn

• true
• False

You should use wheel chocks when the trailer is not equipped with spring brakes, or you are not sure if the trailer has spring brakes.

• True
• False

 You should use the trailer hand brake to straighten out if you go into a trailer skid.

a. True

b. False  

You are driving a combination vehicle when the trailer breaks away and pulls apart the airlines. You should expect the trailer brakes to apply and

• the tractor to lose all air pressure
• the tractor breaks to keep working properly
• the tractor spring brakes to apply
• tractor brakes to lock up

Your 60-foot vehicle is traveling 45 mph: what is the proper following distance?

• 300-foot seconds
• 3 seconds
• 7 seconds
• 700-foot seconds