TX CDL Combination 3

Question 1

The air leakage rate for a combination vehicle (engine off, brakes ON) should not be more than _____ PSI per minute.

Answer 1

4

Question 2

Why should you lock the glad hands to each other or to the storage bracket when you are not towing a trailer?

Answer 2

It will keep dirt and water out of the lines.

Question 3

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:

Answer 3

The tractor protection valve to close.

Question 4

To uncouple a loaded trailer, after the landing gear has made firm contact with the ground, you should

Answer 4

turn the crank a few more times to lift some weight off the tractor.

Question 5

When you test the tractor protection valve, the red air supply control knob should go into the _______ position.

Answer 5

emergency

Question 6

Before you back under a trailer, make sure the:

Answer 6

Trailer brakes are locked.

Question 7

A good illustration of the “crack-the-whip” effect?

Answer 7

When making a quick lane change or sudden movement of the steering wheel, the rear trailer tends to swing out. The force of the rear trailer becomes amplified, causing it to roll over.