MICHIGAN CDL - AIR BRAKES EXAM
QUESTIONS & VERIFIED PASSED
ANSWERS GRADED A+
A low air pressure warning signal should activate: - Correct Answer ✔✔ When tank
pressure falls below 60 psi.
In an air brake system, a low air pressure warning signal must come on if air pressure in
the tanks falls below 60 psi. This warning signal may come in the form of a light, a
buzzer, or a wig wag.
Why should you regularly drain the air tanks? - Correct Answer ✔✔ Because
compressed air contains some water and the water collects in the tanks.
Compressed air usually contains a certain amount of moisture and compressor oil,
which can build up in the air storage tanks and damage the brake system. The tanks
should be drained to clean out these accumulations. On a tank with a manual drain
valve, draining should be performed at the end of each day of driving.
Vehicles equipped with Anti-Lock Braking Systems (ABS) have ____ malfunction lamps
to indicate when the ABS is not working. - Correct Answer ✔✔ Yellow
Vehicles with ABS have yellow malfunction lamps to alert drivers when the braking
systems are not working. Be sure you know where the malfunction lamp on your vehicle
is before beginning a trip.
A dual air brake system: - Correct Answer ✔✔ Consists of two separate air brake
systems that share a single set of controls.
A dual air brake system is made up of two separate air brake systems. The systems
share a single set of brake controls, but each has its own air tanks, hoses, and lines.
One system typically operates the regular brakes on the rear axle or axles while the
other system operates the regular brakes on the front axle.
A safety valve is set to open at ____ pounds per square inch (psi). - Correct Answer
✔✔ 150
The safety valve protects air tanks and the rest of an air brake system from
accumulating too much air pressure. The safety valve is usually set to open at 150 psi.
Air pressure should build up in a single air system within: - Correct Answer ✔✔ Three
minutes.
, In single air systems, air pressure should build from approximately 50 to 90 psi within
three minutes.
Some air brake systems use alcohol: - Correct Answer ✔✔ To reduce the risk of ice
forming in air brake valves.
Some air brake systems contain an alcohol evaporator. This device introduces alcohol
into the braking system to inhibit the formation of ice.
Spring brakes come on: - Correct Answer ✔✔ When too much air pressure is lost.
Spring brakes come on automatically when air pressure drops to an unsafe psi level.
Instead of waiting for the spring brakes to automatically activate, you should safely exit
the road as soon as you notice the low pressure warning signal and bring your vehicle
to a stop while you are still able to control the brakes.
On trucks and buses, where are ABS malfunction lamps located? - Correct Answer ✔✔
On the instrument panel
Tractors, trucks, and buses with Anti-Lock Braking Systems (ABS) have yellow
malfunction lamps located on their instrument panels. Trailers have yellow ABS
malfunction lamps on their left side, either on the front or rear corner.
Before driving a vehicle with a dual air brake system, you must wait for the air
compressor to build a minimum of ____ in both the primary and secondary systems. -
Correct Answer ✔✔ 100 psi
Before driving a vehicle with a dual air brake system, you should wait for the air
compressor to build up at least 100 psi in both the primary and secondary systems.
Anti-Lock Braking Systems (ABS): - Correct Answer ✔✔ Are equipped in addition to
other braking systems and do not reduce normal braking power.
ABS is equipped in addition to a vehicle's normal braking system and it neither
increases nor decreases the vehicle's braking capability. ABS activates during hard
applications of the brake pedal in order to prevent wheels from locking up.
If using air tanks with manually operated drains, how often should you drain the tanks? -
Correct Answer ✔✔ Every day
To prevent the build up of oil and water in a vehicle's air tanks, manually operated air
tank drains should be used at the end of each day of driving.
The parking brake should be: - Correct Answer ✔✔ Used whenever you park your
vehicle.
QUESTIONS & VERIFIED PASSED
ANSWERS GRADED A+
A low air pressure warning signal should activate: - Correct Answer ✔✔ When tank
pressure falls below 60 psi.
In an air brake system, a low air pressure warning signal must come on if air pressure in
the tanks falls below 60 psi. This warning signal may come in the form of a light, a
buzzer, or a wig wag.
Why should you regularly drain the air tanks? - Correct Answer ✔✔ Because
compressed air contains some water and the water collects in the tanks.
Compressed air usually contains a certain amount of moisture and compressor oil,
which can build up in the air storage tanks and damage the brake system. The tanks
should be drained to clean out these accumulations. On a tank with a manual drain
valve, draining should be performed at the end of each day of driving.
Vehicles equipped with Anti-Lock Braking Systems (ABS) have ____ malfunction lamps
to indicate when the ABS is not working. - Correct Answer ✔✔ Yellow
Vehicles with ABS have yellow malfunction lamps to alert drivers when the braking
systems are not working. Be sure you know where the malfunction lamp on your vehicle
is before beginning a trip.
A dual air brake system: - Correct Answer ✔✔ Consists of two separate air brake
systems that share a single set of controls.
A dual air brake system is made up of two separate air brake systems. The systems
share a single set of brake controls, but each has its own air tanks, hoses, and lines.
One system typically operates the regular brakes on the rear axle or axles while the
other system operates the regular brakes on the front axle.
A safety valve is set to open at ____ pounds per square inch (psi). - Correct Answer
✔✔ 150
The safety valve protects air tanks and the rest of an air brake system from
accumulating too much air pressure. The safety valve is usually set to open at 150 psi.
Air pressure should build up in a single air system within: - Correct Answer ✔✔ Three
minutes.
, In single air systems, air pressure should build from approximately 50 to 90 psi within
three minutes.
Some air brake systems use alcohol: - Correct Answer ✔✔ To reduce the risk of ice
forming in air brake valves.
Some air brake systems contain an alcohol evaporator. This device introduces alcohol
into the braking system to inhibit the formation of ice.
Spring brakes come on: - Correct Answer ✔✔ When too much air pressure is lost.
Spring brakes come on automatically when air pressure drops to an unsafe psi level.
Instead of waiting for the spring brakes to automatically activate, you should safely exit
the road as soon as you notice the low pressure warning signal and bring your vehicle
to a stop while you are still able to control the brakes.
On trucks and buses, where are ABS malfunction lamps located? - Correct Answer ✔✔
On the instrument panel
Tractors, trucks, and buses with Anti-Lock Braking Systems (ABS) have yellow
malfunction lamps located on their instrument panels. Trailers have yellow ABS
malfunction lamps on their left side, either on the front or rear corner.
Before driving a vehicle with a dual air brake system, you must wait for the air
compressor to build a minimum of ____ in both the primary and secondary systems. -
Correct Answer ✔✔ 100 psi
Before driving a vehicle with a dual air brake system, you should wait for the air
compressor to build up at least 100 psi in both the primary and secondary systems.
Anti-Lock Braking Systems (ABS): - Correct Answer ✔✔ Are equipped in addition to
other braking systems and do not reduce normal braking power.
ABS is equipped in addition to a vehicle's normal braking system and it neither
increases nor decreases the vehicle's braking capability. ABS activates during hard
applications of the brake pedal in order to prevent wheels from locking up.
If using air tanks with manually operated drains, how often should you drain the tanks? -
Correct Answer ✔✔ Every day
To prevent the build up of oil and water in a vehicle's air tanks, manually operated air
tank drains should be used at the end of each day of driving.
The parking brake should be: - Correct Answer ✔✔ Used whenever you park your
vehicle.
