District of Columbia Air Brakes Practice Test

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This is our District of Columbia Air Brakes Practice Quiz and Practice Test compiled of 25 questions each. Each question is worth four points for a total of 100 possible points. A passing score is 80%.

The Air Brakes Practice Quiz reveals the correct answer during each question to help you study for the actual Air Brakes exam. The Air Brakes Practice Test doesn’t reveal the correct answers until the test is over.

The questions and answers are given in random order each time you retake the test. When you are finished testing, simply click on the “Get Results” button to see your test results. Clicking on the blue “List” button will reveal a list of all the questions you answered correctly and incorrectly. To take the test again, just refresh your browser window. It’s that easy.

Press the start button to begin your free Air Brakes Practice Quiz. Good luck!

Air Brakes CDL Practice Quiz

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Congratulations! You have completed the Air Brakes CDL Practice Quiz. You scored %%SCORE%% out of %%TOTAL%%. Your performance has been rated as %%RATING%%

Your answers are highlighted below.

Question 1

The ______ forces the brake ______ away from each other and against the inside of the brake drum.

A	pressure valve, boots
B	valve spring, shoes
C	s-cam, shoes
D	coil, boots

Question 2

Brake drums are:

A	used to hold the brake shoes and linings.
B	bolted securely to the wheels.
C	located on either end of the vehicle's axles.
D	all of these.

Question 3

When should the parking brake not be used?

A	When the combined weight of your truckload and vehicle exceeds five tons.
B	When the air pressure is low.
C	When the temperature is below freezing.
D	When the brakes are hot.

Question 4

Air tanks must be drained to:

A	prevent someone from moving the vehicle.
B	prevent them from freezing during cold temperatures.
C	completely empty air out of the tank.
D	drain oil and moisture from the tank.

Question 5

The safety valve in the air compressor tank should open at ______ psi.

A	200
B	125
C	175
D	150

Question 6

In an air brake system, the air compressor pumps air into the ______.

A	hydraulic brakes
B	air tank drains
C	brake system
D	storage tanks

Question 7

The most common type of foundation brakes are ______ brakes.

A	wedge
B	s-cam drum
C	shoe
D	disc

Question 8

When should the air tanks be drained?

A	Once a week.
B	Once a day.
C	Before every trip.
D	Every 1,000 miles.

Question 9

What is a good indication that your truck's single brake system needs to be adjusted?

A	When the compressor shuts off between 70 to 90 psi.
B	When pressure increases from 85 to 100 psi within 45 seconds.
C	When pressure increases from 50 to 75 psi within three minutes.
D	When the governor switch stops between 75 to 90 psi.

Question 10

The emergency brake system uses the ______ and the ______ to stop the vehicle during a brake system failure.

A	service brake, emergency brake systems
B	disc brake, parking brake systems
C	service brake, parking brake systems
D	disc brake, emergency brake systems

Question 11

Are front wheel brakes good under all conditions?

A	Only if they are drum brakes.
B	Only if they are disc brakes.
C	No.
D	Yes.

Question 12

What will happen if your air compressor stops working?

A	You will still have some air pressure left in the air tanks.
B	Nothing will happen.
C	Your brakes will instantly lock up.
D	You will instantly lose braking power.

Question 13

In a straight truck or passenger bus, with the engine off and the brakes released, air loss should not exceed ______ psi in ______ seconds.

A	two, sixty
B	one, sixty
C	three, sixty
D	one, thirty

Question 14

Some air brake systems are equipped with an alcohol evaporator. The purpose of the alcohol evaporator is to______.

A	evaporate any alcohol, which can damage the brake system
B	reduce the risk of ice in the air brake valves
C	remove fuel from the air lines
D	remove oil from the air lines

Question 15

Vehicles equipped with air brakes are required to have a low air pressure warning signal. True or False?

A	True
B	False

Question 16

What two substances usually found in compressed air are harmful to the brake system?

A	Compressed air does not contain any of these substances.
B	Dust and compressor oil.
C	Dust and water.
D	Water and compressor oil.

Question 17

Air brake systems are a combination of which three braking systems?

A	The emergency brake system, parking brake system, and foundation brake system.
B	The parking brake system, service brake system, and emergency brake system.
C	The service brake system, manual brake system, and disc brake system.
D	The disc brake system, drum brake system, and foundation brake system.

Question 18

Compressed air is let out of the system by ______.

A	pushing down on the brake pedal
B	activating the parking brake
C	letting up on the brake pedal
D	activating the emergency brake

Question 19

The supply pressure gauge is used for what purpose?

A	None of these.
B	To let you know how much oxygen is in the air tanks.
C	To let you know how much water is in the air tank.
D	To let you know how much diesel fuel is in the vehicle.

Question 20

The air storage tanks are used to hold ______.

A	oxygen and helium
B	compressed air
C	compressed gas
D	nitrogen and oxygen

Question 21

What should you do when you see the low pressure warning?

A	Safely bring the automobile to a stop while you still have control over the brakes.
B	Check your air pressure gauge and drive at highway speeds.
C	Stay calm and wait for the air brakes to come on automatically.
D	Pump the brake pedal hard until you come to a stop.

Question 22

The service brake system:

A	is only on automobiles with hydraulic brakes.
B	is known as an official vehicle inspection.
C	applies and releases the vehicle's brakes using the brake pedal.
D	is only found on automobiles with hydraulic brakes.

Question 23

What does it mean when the safety valve releases air?

A	Something is malfunctioning, and you should have the vehicle checked by a mechanic.
B	The air pressure has exceeded 150 psi.
C	There is way too much air in the air compressor.
D	All of these.

Question 24

Spring brakes are ______.

A	specialized brakes only to be used during warm weather
B	springs that press the brakes on to stop the vehicle if the air brakes leak out
C	the spring that is attached to the brake pedal
D	used for parking

Question 25

The device that protects the tank and the rest of the air brake system from too much pressure is known as the:

A	governor.
B	safety valve.
C	air tank drain.
D	application pressure gauge.

Once you are finished, click the button below. Any items you have not completed will be marked incorrect. Get Results

There are 25 questions to complete.

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Remember, the Air Brakes Practice Test doesn’t reveal the correct answers until the test is over. The questions and answers are given in random order each time you retake the test. When you are finished testing, simply click on the “Get Results” button to see your test results. Clicking on the blue “List” button will reveal a list of all the questions you answered correctly and incorrectly. To take the test again, just refresh your browser window.

Press the start button to begin your free Air Brakes Practice Test. Good luck!

Air Brakes CDL Practice Test

Please wait while the activity loads.
If this activity does not load, try refreshing your browser. Also, this page requires javascript. Please visit using a browser with javascript enabled.

If loading fails, click here to try again

Start

Congratulations! You have completed the Air Brakes CDL Practice Test. You scored %%SCORE%% out of %%TOTAL%%. Your performance has been rated as %%RATING%%

Your answers are highlighted below.

Question 1

Air brake systems are a combination of which three braking systems?

A	The service brake system, manual brake system, and disc brake system.
B	The parking brake system, service brake system, and emergency brake system.
C	The emergency brake system, parking brake system, and foundation brake system.
D	The disc brake system, drum brake system, and foundation brake system.

Question 2

What should you do when you see the low pressure warning?

A	Pump the brake pedal hard until you come to a stop.
B	Check your air pressure gauge and drive at highway speeds.
C	Stay calm and wait for the air brakes to come on automatically.
D	Safely bring the automobile to a stop while you still have control over the brakes.

Question 3

Compressed air is let out of the system by ______.

A	letting up on the brake pedal
B	activating the emergency brake
C	pushing down on the brake pedal
D	activating the parking brake

Question 4

The air storage tanks are used to hold ______.

A	compressed air
B	oxygen and helium
C	nitrogen and oxygen
D	compressed gas

Question 5

The service brake system:

A	is known as an official vehicle inspection.
B	is only on automobiles with hydraulic brakes.
C	is only found on automobiles with hydraulic brakes.
D	applies and releases the vehicle's brakes using the brake pedal.

Question 6

Brake drums are:

A	bolted securely to the wheels
B	all of these.
C	located on either end of the vehicle's axles.
D	used to hold the brake shoes and linings.

Question 7

When should the air tanks be drained?

A	Before every trip.
B	Once a day.
C	Once a week.
D	Every 1,000 miles.

Question 8

When should the parking brake not be used?

A	When the brakes are hot.
B	When the combined weight of your truckload and vehicle exceeds five tons.
C	When the air pressure is low.
D	When the temperature is below freezing.

Question 9

Spring brakes are ______.

A	the spring that is attached to the brake pedal
B	specialized brakes only to be used during warm weather
C	springs that press the brakes on to stop the vehicle if the air brakes leak out
D	used for parking

Question 10

What does it mean when the safety valve releases air?

A	Something is malfunctioning, and you should have the vehicle checked by a mechanic.
B	All of these.
C	There is way too much air in the air compressor.
D	The air pressure has exceeded 150 psi.

Question 11

The device that protects the tank and the rest of the air brake system from too much pressure is known as the:

A	application pressure gauge.
B	safety valve.
C	governor.
D	air tank drain.

Question 12

What is a good indication that your automobile's single brake system needs to be adjusted?

A	When pressure increases from 85 to 100 psi within 45 seconds.
B	When the governor switch stops between 75 to 90 psi.
C	When the compressor shuts off between 70 to 90 psi.
D	When pressure increases from 50 to 75 psi within three minutes.

Question 13

In a straight truck or passenger bus, with the engine off and the brakes released, air loss should not exceed ______ psi in ______ seconds.

A	three, sixty
B	one, thirty
C	two, sixty
D	one, sixty

Question 14

The supply pressure gauge is used for what purpose?

A	None of these.
B	To let you know how much water is in the air tank.
C	To let you know how much oxygen is in the air tanks.
D	To let you know how much diesel fuel is in the vehicle.

Question 15

What two substances usually found in compressed air are harmful to the brake system?

A	Water and compressor oil.
B	Dust and compressor oil.
C	Compressed air does not contain any of these substances.
D	Dust and water.

Question 16

The safety valve in the air compressor tank should open at ______ psi.

A	175
B	200
C	150
D	125

Question 17

Some air brake systems are equipped with an alcohol evaporator. The purpose of the alcohol evaporator is to______.

A	evaporate any alcohol, which can damage the brake system
B	remove oil from the air lines
C	remove fuel from the air lines
D	reduce the risk of ice in the air brake valves

Question 18

The ______ forces the brake ______ away from each other and against the inside of the brake drum.

A	pressure valve, boots
B	s-cam, shoes
C	coil, boots
D	valve spring, shoes

Question 19

The emergency brake system uses the ______ and the ______ to stop the vehicle during a brake system failure.

A	service brake, emergency brake systems
B	service brake, parking brake systems
C	disc brake, emergency brake systems
D	disc brake, parking brake systems

Question 20

What will happen if your air compressor stops working?

A	Nothing will happen.
B	You will instantly lose braking power.
C	You will still have some air pressure left in the air tanks.
D	Your brakes will instantly lock up.

Question 21

Vehicles equipped with air brakes are required to have a low air pressure warning signal. True or False?

A	False
B	True

Question 22

Are front wheel brakes good under all conditions?

A	Yes.
B	Only if they are drum brakes.
C	No.
D	Only if they are disc brakes.

Question 23

The most common type of foundation brakes are ______ brakes.

A	shoe
B	wedge
C	disc
D	s-cam drum

Question 24

Air tanks must be drained to:

A	prevent them from freezing during cold temperatures.
B	prevent someone from moving the vehicle.
C	drain oil and moisture from the tank.
D	completely empty air out of the tank.

Question 25

In an air brake system, the air compressor pumps air into the ______.

A	storage tanks
B	hydraulic brakes
C	air tank drains
D	brake system

Once you are finished, click the button below. Any items you have not completed will be marked incorrect. Get Results

There are 25 questions to complete.

←

List

→

Return

Shaded items are complete.

1	2	3	4	5
6	7	8	9	10
11	12	13	14	15
16	17	18	19	20
21	22	23	24	25
End

Return

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