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%% Pass your Air Brakes Knowledge Exam the first time! Click here to get the Complete CDL Cheat Sheet Study Package for all 50 states!

Your answers are highlighted below.

Question 1

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	You will instantly lose braking power.
D	Your brakes will instantly lock up.

Question 2

Compressed air is let out of the system by ______.

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

Question 3

Air tanks must be drained to:

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

Question 4

The most common type of foundation brakes are ______ brakes.

A	shoe
B	s-cam drum
C	wedge
D	disc

Question 5

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

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

Question 6

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

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

Question 7

The service brake system:

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

Question 8

The air storage tanks are used to hold ______.

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

Question 9

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 fuel from the air lines
C	remove oil from the air lines
D	reduce the risk of ice in the air brake valves

Question 10

When should the parking brake not be used?

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

Question 11

Are front wheel brakes good under all conditions?

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

Question 12

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

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

Question 13

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

A	175
B	125
C	150
D	200

Question 14

When should the air tanks be drained?

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

Question 15

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

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

Question 16

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

A	False
B	True

Question 17

The supply pressure gauge is used for what purpose?

A	To let you know how much diesel fuel is in the vehicle.
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	None of these.

Question 18

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

Question 19

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 20

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 21

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

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

Question 22

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

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

Question 23

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

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

Question 24

What does it mean when the safety valve releases air?

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

Question 25

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

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%% Pass your Air Brakes Knowledge Exam the first time! Click here to get the Complete CDL Cheat Sheet Study Package for all 50 states!

Your answers are highlighted below.

Question 1

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

A	False
B	True

Question 2

What will happen if your air compressor stops working?

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

Question 3

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

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

Question 4

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	reduce the risk of ice in the air brake valves
D	remove fuel from the air lines

Question 5

The air storage tanks are used to hold ______.

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

Question 6

What is a good indication that your automobile'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 7

The most common type of foundation brakes are ______ brakes.

A	wedge
B	disc
C	shoe
D	s-cam drum

Question 8

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	valve spring, shoes
D	coil, boots

Question 9

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

A	The disc brake system, drum 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 emergency brake system, parking brake system, and foundation brake system.

Question 10

Are front wheel brakes good under all conditions?

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

Question 11

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

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

Question 12

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

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

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

Question 14

Air tanks must be drained to:

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

Question 15

When should the parking brake not be used?

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

Question 16

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 17

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	used for parking
D	the spring that is attached to the brake pedal

Question 18

Compressed air is let out of the system by ______.

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

Question 19

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

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

Question 20

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

A	125
B	150
C	200
D	175

Question 21

When should the air tanks be drained?

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

Question 22

Brake drums are:

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

Question 23

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

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

Question 24

What does it mean when the safety valve releases air?

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

Question 25

The supply pressure gauge is used for what purpose?

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

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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