CDL Combination Vehicles Practice Test 2

Question 1

The trailer protection valve is designed to close automatically if the air pressure reaches the range of

Accepted Answer

20 - 45 psi

Answer

0 - 9 psi

Answer

10 - 19 psi

Answer

46 - 60 psi

Question 2

You should always test the trailer brakes before driving by

Accepted Answer

Options 1st & 2nd

Answer

Using the hand valve

Answer

Pulling the air supply control

Answer

Using the foot brake

Question 3

If you are parking a trailer without spring brakes, which of the following should you use?

Accepted Answer

Wheel chocks

Answer

Parking brake

Answer

Emergency brake

Answer

Trailer hand brakes

Question 4

The coupling device used to connect the service and emergency air lines from the truck to the trailer is known as?

Accepted Answer

Glad hands

Answer

Trailer air supply control

Answer

Relay valve

Answer

Cut-out cocks

Question 5

Which of the following is a valve used at the back of a trailer that allows the closing of the air lines when another trailer is not being towed?

Accepted Answer

Cut-out cocks

Answer

Drain valve

Answer

Dummy coupler

Answer

Tractor protection valve

Question 6

Which of the following devices should you use to prevent water and dirt from getting into the coupler and air lines when they are not in use?

Accepted Answer

Dead end or dummy couplers

Answer

Shut-off valves

Answer

Relay valves

Answer

Tractor protection valve

Question 7

How are the air lines color coded to keep them from getting mixed up?

Accepted Answer

Emergency line is RED. Service line is BLUE.

Answer

Emergency line is BLUE. Service line is RED.

Answer

Emergency line is RED. Service line is WHITE.

Answer

Emergency line is GREEN. Service line is BLUE.

Question 8

You could experience steering problems because of friction between the tractor and trailer if you do not lubricate which of the following?

Accepted Answer

Fifth wheel plate

Answer

Relay valves

Answer

Glad hands

Answer

Dead end couplers

Question 9

If you are lowering the landing gear of a loaded trailer, you should

Accepted Answer

Turn the crank in low gear a few extra turns after firm contact with the ground

Answer

Lift the trailer off of the fifth wheel

Answer

Lower the landing gear until it makes firm contact with the ground

Answer

Turn the crank in high gear a few extra turns after firm contact with the ground