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Free CDL - Section 5 - Air Brakes

You are about to take a FREE Sample of the CDL - Section 5 - Air Brakes. The sample test consists of 10 multiple choice questions and answers.

Please select the best answer for each question below and then click "Submit."

1. What does the air compressor do?

c.
The air compressor puts alcohol into the air system.
b.
The air compressor is used to hold compressed air.
a.
The air compressor pumps air into the storage tanks (reservoirs).

2. What does the air compressor governor do?

d.
None of the above
c.
The governor pumps air into the air storage tanks.
b.
The governor is used to hold compressed air.
a.
The governor controls when the air compressor will pump air into the air storage tanks.

3. When air tank pressure rises to the "cut-out" level, the governor stops the compressor from pumping air. What level is the "cut-out" level?

c.
Around 150 pounds per square inch or "psi"
b.
Around 100 pounds per square inch or "psi"
a.
Around 125 pounds per square inch or "psi"

4. When the tank pressure falls to the "cut-in" pressure, the governor allows the compressor to start pumping again. What is the "cut-in" level?

c.
Around 50 pounds per square inch or "psi"
b.
Around 100 pounds per square inch or "psi"
a.
Around 125 pounds per square inch or "psi"

5. Compressed air usually has some water and some compressor oil in it which is bad for the air brake system. Why is it bad for the air brake system?

c.
The presence of oil and water in the tanks may create too much pressure in the tanks.
b.
The air can become polluted and impact the function of the brakes.
a.
The water can freeze in cold weather and cause brake failure.

6. Tractor and straight truck spring brakes will come on when the air pressure drops to what range?

d.
None of the above
c.
5 to 15 psi
b.
40 to 85 psi
a.
20 to 45 psi

7. When the spring brakes are on, what should you not do?

d.
All of the above
c.
Honk the horn.
b.
Put on the parking brakes.
a.
Push the brake pedal down.

8. A dual air brake system has two separate air brake systems which use a single set of brake controls. True or False?

b.
False
a.
True

9. What are the maximum leakage rates?

c.
If the air pressure falls more than 50 psi in one minute for single vehicles, then the air loss rate is too much.
b.
If the air pressure falls more than 30 psi in one minute for single vehicles, then the air loss rate is too much.
a.
If the air pressure falls more than 3 psi in one minute for single vehicles, then the air loss rate is too much.

10. What is the controlled braking method?

b.
You apply the brakes all the way, then release when they lock up, and as soon as the wheels start rolling, repeat.
a.
You apply the brakes as hard as you can without locking the wheels.