CDL Air Brakes Exam 2025 Questions
and Answers
The driver must be able to see a warning that is given before air pressure in the
service air tanks falls below:
a) 80 psi
b) 40 psi
c) 20 psi
d) 60 psi - --CORRECT ANSWER--D
Slack adjusters:
a) Never need to be adjusted
b) Should only be adjusted by a qualified mechanic
c) Can be adjusted manually or automatically
d) Should travel at least two inches from where the push rod is attached - --
CORRECT ANSWER--C
An air tank is equipped with a drain valve to remove:
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,a) Air and water
b) Oil and air
c) Water and oil
d) Dirt and oil - --CORRECT ANSWER--C
A dual air brake system:
a) Has two air brake systems and one set of controls
b) Takes less time to build air pressure
c) Has one set of air tanks and hoses
d) Must have two warning alarms - --CORRECT ANSWER--A
During normal driving, spring brakes are usually held back by:
a) Spring pressure
b) Bolts or clamps
c) Centrifugal force
d) Air pressure - --CORRECT ANSWER--D
Vehicles with air brakes must have:
a) At least two air tanks
b) An air pressure gauge to show the pressure available for braking
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, c) An air pressure gauge, to show air used by the brake chambers for braking
d) None of the above - --CORRECT ANSWER--B
Your vehicle's single brake system needs adjustment if:
a) Pressure builds from 50 to 75 psi within three minutes
b) Pressure builds from 85 to 100 psi within 45 secnds
c) The compressor cuts out between 70 to 90 psi
d) The governor stops between 75 to 90 psi - --CORRECT ANSWER--C
If the air compressor should develop a leak, what keeps the air in the tanks?
a) The tractor protection valve
b) The emergency relay valve
c) The one way check valve
d) The air compressor - --CORRECT ANSWER--C
You should avoid using the parking brake:
a) On steep hills
b) If the air pressure is low
c) When the brakes are hot
d) Anytime you park - --CORRECT ANSWER--C
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and Answers
The driver must be able to see a warning that is given before air pressure in the
service air tanks falls below:
a) 80 psi
b) 40 psi
c) 20 psi
d) 60 psi - --CORRECT ANSWER--D
Slack adjusters:
a) Never need to be adjusted
b) Should only be adjusted by a qualified mechanic
c) Can be adjusted manually or automatically
d) Should travel at least two inches from where the push rod is attached - --
CORRECT ANSWER--C
An air tank is equipped with a drain valve to remove:
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 1
,a) Air and water
b) Oil and air
c) Water and oil
d) Dirt and oil - --CORRECT ANSWER--C
A dual air brake system:
a) Has two air brake systems and one set of controls
b) Takes less time to build air pressure
c) Has one set of air tanks and hoses
d) Must have two warning alarms - --CORRECT ANSWER--A
During normal driving, spring brakes are usually held back by:
a) Spring pressure
b) Bolts or clamps
c) Centrifugal force
d) Air pressure - --CORRECT ANSWER--D
Vehicles with air brakes must have:
a) At least two air tanks
b) An air pressure gauge to show the pressure available for braking
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 2
, c) An air pressure gauge, to show air used by the brake chambers for braking
d) None of the above - --CORRECT ANSWER--B
Your vehicle's single brake system needs adjustment if:
a) Pressure builds from 50 to 75 psi within three minutes
b) Pressure builds from 85 to 100 psi within 45 secnds
c) The compressor cuts out between 70 to 90 psi
d) The governor stops between 75 to 90 psi - --CORRECT ANSWER--C
If the air compressor should develop a leak, what keeps the air in the tanks?
a) The tractor protection valve
b) The emergency relay valve
c) The one way check valve
d) The air compressor - --CORRECT ANSWER--C
You should avoid using the parking brake:
a) On steep hills
b) If the air pressure is low
c) When the brakes are hot
d) Anytime you park - --CORRECT ANSWER--C
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