Iowa Air Brakes Practice Test

This is our Iowa 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

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 Quiz. You scored %%SCORE%% out of %%TOTAL%%. Your performance has been rated as %%RATING%%

Your answers are highlighted below.

Question 1

The supply pressure gauge is used for what purpose?

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

Question 2

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

A	125
B	200
C	175
D	150

Question 3

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	air tank drain.
C	governor.
D	application pressure gauge.

Question 4

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

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

Question 5

Are front wheel brakes good under all conditions?

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

Question 6

Air tanks must be drained to:

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

Question 7

What does it mean when the safety valve releases air?

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

Question 8

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

A	False
B	True

Question 9

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

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

Question 10

What is a good indication that your truck'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 pressure increases from 50 to 75 psi within three minutes.
D	When the compressor shuts off between 70 to 90 psi.

Question 11

What will happen if your air compressor stops working?

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

Question 12

When should the parking brake not be used?

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

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

Question 14

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

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

Question 15

The air storage tanks are used to hold ______.

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

Question 16

Spring brakes are ______.

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

Question 17

The most common type of foundation brakes are ______ brakes.

A	shoe
B	disc
C	s-cam drum
D	wedge

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

Question 19

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

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

Question 20

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 21

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 emergency brake
D	activating the parking brake

Question 22

The service brake system:

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

Question 23

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

Question 24

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

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

Question 25

When should the air tanks be drained?

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

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

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

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

Question 2

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	Dust and water.
D	Compressed air does not contain any of these substances.

Question 3

The service brake system:

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

Question 4

Brake drums are:

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

Question 5

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

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

Question 6

The most common type of foundation brakes are ______ brakes.

A	s-cam drum
B	shoe
C	disc
D	wedge

Question 7

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 8

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

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

Question 9

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	air tank drain.
C	governor.
D	application pressure gauge.

Question 10

What does it mean when the safety valve releases air?

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

Question 11

The air storage tanks are used to hold ______.

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

Question 12

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

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

Question 13

When should the air tanks be drained?

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

Question 14

Spring brakes are ______.

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

Question 15

What will happen if your air compressor stops working?

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

Question 16

When should the parking brake not be used?

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

Question 17

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

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

Question 18

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

A	True
B	False

Question 19

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

A	125
B	200
C	175
D	150

Question 20

Compressed air is let out of the system by ______.

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

Question 21

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 22

Are front wheel brakes good under all conditions?

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

Question 23

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	Pump the brake pedal hard until you come to a stop.
C	Stay calm and wait for the air brakes to come on automatically.
D	Check your air pressure gauge and drive at highway speeds.

Question 24

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 oxygen is in the air tanks.
D	To let you know how much water is in the air tank.

Question 25

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

Back to Iowa CDL Practice Test

5/5 - (1 vote)