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!
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
Safely bring the automobile to a stop while you still have control over the brakes.
C
Pump the brake pedal hard until you come to a stop.
D
Check your air pressure gauge and drive at highway speeds.
Question 3
The safety valve in the air compressor tank should open at ______ psi.
A
125
B
150
C
200
D
175
Question 4
The air storage tanks are used to hold ______.
A
oxygen and helium
B
compressed gas
C
compressed air
D
nitrogen and oxygen
Question 5
Brake drums are:
A
all of these.
B
used to hold the brake shoes and linings.
C
bolted securely to the wheels.
D
located on either end of the vehicle's axles.
Question 6
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 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 7
Spring brakes are ______.
A
springs that press the brakes on to stop the vehicle if the air brakes leak out
B
specialized brakes only to be used during warm weather
C
used for parking
D
the spring that is attached to the brake pedal
Question 8
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, parking brake systems
D
disc brake, emergency brake systems
Question 9
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
evaporate any alcohol, which can damage the brake system
D
remove oil from the air lines
Question 10
When should the air tanks be drained?
A
Once a week.
B
Before every trip.
C
Every 1,000 miles.
D
Once a day.
Question 11
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
coil, boots
D
pressure valve, boots
Question 12
In an air brake system, the air compressor pumps air into the ______.
A
storage tanks
B
air tank drains
C
brake system
D
hydraulic brakes
Question 13
Vehicles equipped with air brakes are required to have a low air pressure warning signal. True or False?
A
False
B
True
Question 14
Compressed air is let out of the system by ______.
A
activating the parking brake
B
pushing down on the brake pedal
C
activating the emergency brake
D
letting up on the brake pedal
Question 15
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 disc brake system, drum brake system, and foundation brake system.
C
The parking brake system, service brake system, and emergency brake system.
D
The emergency brake system, parking brake system, and foundation brake system.
Question 16
The most common type of foundation brakes are ______ brakes.
A
disc
B
s-cam drum
C
wedge
D
shoe
Question 17
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 brakes are hot.
D
When the combined weight of your truckload and vehicle exceeds five tons.
Question 18
What two substances usually found in compressed air are harmful to the brake system?
A
Dust and water.
B
Dust and compressor oil.
C
Water and compressor oil.
D
Compressed air does not contain any of these substances.
Question 19
What does it mean when the safety valve releases air?
A
All of these.
B
The air pressure has exceeded 150 psi.
C
Something is malfunctioning, and you should have the vehicle checked by a mechanic.
D
There is way too much air in the air compressor.
Question 20
What will happen if your air compressor stops working?
A
You will instantly lose braking power.
B
Nothing will happen.
C
Your brakes will instantly lock up.
D
You will still have some air pressure left in the air tanks.
Question 21
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 22
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 23
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
application pressure gauge.
C
governor.
D
safety valve.
Question 24
The service brake system:
A
is only found 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 on automobiles with hydraulic brakes.
Question 25
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
None of these.
D
To let you know how much water is in the air tank.
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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!