CDL CLASS B QUIZ 2 CERTIFICATION
EVALUATION 2026 FULL QUESTIONS AND
CORRECT ANSWERS
◉ What is a supply pressure gauge used for?
Answer: These gauges tell you how much pressure is in the
air tanks.
◉ All vehicles with air brakes must have a low air pressure warning
signal. True or False?
Answer: True (A low air pressure warning signal is required on
vehicles with air brakes. A warning signal you can see must come on
before the air pressure in the tanks falls below 60 psi.)
◉ What are spring brakes?
Answer: emergency brakes and parking brakes. They must be held
on by mechanical force
◉ Front wheel brakes are good under all conditions. True or False?
Answer: True (Limiting valves were used to reduce the chance of the
front wheels skidding on slippery surfaces.
However, they actually reduce the stopping power of the vehicle)
,◉ How do you know if your vehicle is equipped with antilock
brakes?
Answer: Check the certification label for the date of manufacture to
determine if your vehicle is equipped with
◉ What is a dual air brake system?
Answer: has two separate air brake systems, which use a single
set of brake controls. Each system has its own air tanks, hoses, lines,
etc. One system typically operates the regular brakes on the rear axle
or axles. The other system operates the regular brakes on the front
axle
◉ What are the slack adjusters?
Answer: is a lever arm connected to the brake chamber's push rod at
the clevis assembly. it adjusts the brakes to make up for lining wear.
◉ How can you check slack adjusters?
Answer: Park on level ground and chock the wheels to prevent the
vehicle from moving. Release the parking brakes
so you can move the slack adjusters. Use gloves and pull hard on
each slack adjuster that you can reach. If a slack adjuster moves
more than about one inch where the push rod attaches to it, it
,probably needs adjustment. Adjust it or have it adjusted. Vehicles
with too much brake slack can be very hard to stop.
◉ How can you test the low pressure warning signal?
Answer: Shut the engine off when you have enough air pressure so
that the low pressure warning signal is not on. Turn the electrical
power on and step on and off the brake pedal to reduce air tank
pressure. The low air pressure warning signal must come on before
the pressure drops to less than 60 psi in the air
tank (or tank with the lowest air pressure, in dual
air systems).
◉ How can you check that the spring brakes come on automatically?
Answer: Continue to fan off the air
pressure by stepping on and off the brake pedal to
reduce tank pressure. The tractor protection valve
and parking brake valve should close (pop out) on
a tractor-trailer combination vehicle and the parking brake valve
should close (pop out) on other combination and single vehicle
types when the air pressure falls to the manufacturer's specification
◉ What are the maximum leakage rates?
Answer: With a fully-charged air
, system (typically 125 psi), turn off the engine, release the parking
brake (push in); and time the air pressure drop. The loss rate should
be less
than two psi in one minute for single vehicles and less than three psi
in one minute for combination vehicles.
◉ Why should you be in the proper gear before starting down a hill?
Answer: Otherwise the brakes can
overheat and lose their braking power.
◉ What factors can cause brakes to fade or fail?
Answer: The heat a drum can take without damage depends on how
hard and how long the brakes are used. Too much heat can make the
brakes stop working.
◉ The use of brakes on a long, steep downgrade is only a
supplement to the braking effect of the engine. True or False?
Answer: True
◉ If you are away from your vehicle only a short time, you do not
need to use the parking brake. True or False?
Answer: False. (Always use the parking brakes when parking)
◉ How often should you drain air tanks?
EVALUATION 2026 FULL QUESTIONS AND
CORRECT ANSWERS
◉ What is a supply pressure gauge used for?
Answer: These gauges tell you how much pressure is in the
air tanks.
◉ All vehicles with air brakes must have a low air pressure warning
signal. True or False?
Answer: True (A low air pressure warning signal is required on
vehicles with air brakes. A warning signal you can see must come on
before the air pressure in the tanks falls below 60 psi.)
◉ What are spring brakes?
Answer: emergency brakes and parking brakes. They must be held
on by mechanical force
◉ Front wheel brakes are good under all conditions. True or False?
Answer: True (Limiting valves were used to reduce the chance of the
front wheels skidding on slippery surfaces.
However, they actually reduce the stopping power of the vehicle)
,◉ How do you know if your vehicle is equipped with antilock
brakes?
Answer: Check the certification label for the date of manufacture to
determine if your vehicle is equipped with
◉ What is a dual air brake system?
Answer: has two separate air brake systems, which use a single
set of brake controls. Each system has its own air tanks, hoses, lines,
etc. One system typically operates the regular brakes on the rear axle
or axles. The other system operates the regular brakes on the front
axle
◉ What are the slack adjusters?
Answer: is a lever arm connected to the brake chamber's push rod at
the clevis assembly. it adjusts the brakes to make up for lining wear.
◉ How can you check slack adjusters?
Answer: Park on level ground and chock the wheels to prevent the
vehicle from moving. Release the parking brakes
so you can move the slack adjusters. Use gloves and pull hard on
each slack adjuster that you can reach. If a slack adjuster moves
more than about one inch where the push rod attaches to it, it
,probably needs adjustment. Adjust it or have it adjusted. Vehicles
with too much brake slack can be very hard to stop.
◉ How can you test the low pressure warning signal?
Answer: Shut the engine off when you have enough air pressure so
that the low pressure warning signal is not on. Turn the electrical
power on and step on and off the brake pedal to reduce air tank
pressure. The low air pressure warning signal must come on before
the pressure drops to less than 60 psi in the air
tank (or tank with the lowest air pressure, in dual
air systems).
◉ How can you check that the spring brakes come on automatically?
Answer: Continue to fan off the air
pressure by stepping on and off the brake pedal to
reduce tank pressure. The tractor protection valve
and parking brake valve should close (pop out) on
a tractor-trailer combination vehicle and the parking brake valve
should close (pop out) on other combination and single vehicle
types when the air pressure falls to the manufacturer's specification
◉ What are the maximum leakage rates?
Answer: With a fully-charged air
, system (typically 125 psi), turn off the engine, release the parking
brake (push in); and time the air pressure drop. The loss rate should
be less
than two psi in one minute for single vehicles and less than three psi
in one minute for combination vehicles.
◉ Why should you be in the proper gear before starting down a hill?
Answer: Otherwise the brakes can
overheat and lose their braking power.
◉ What factors can cause brakes to fade or fail?
Answer: The heat a drum can take without damage depends on how
hard and how long the brakes are used. Too much heat can make the
brakes stop working.
◉ The use of brakes on a long, steep downgrade is only a
supplement to the braking effect of the engine. True or False?
Answer: True
◉ If you are away from your vehicle only a short time, you do not
need to use the parking brake. True or False?
Answer: False. (Always use the parking brakes when parking)
◉ How often should you drain air tanks?
