CDL AIR BRAKES QUESTIONS &
ANSWERS 100% CORRECT!!
Oil and water usually collect in compressed air tanks. If you do not have an
automatic tank drain, when should you drain the air tanks? - ANSWERAfter every
working day
EXPLANATION:
If your vehicle does not have automatic air tank drains, drain your air tanks at the
end of each working day to remove moisture and oil. Otherwise, the brakes could
fail.
What is the S-cam used for? - ANSWERTo apply the brakes.
Explanation:
When you push the brake pedal, air is let into each brake chamber. Air pressure
pushes the rod out, moving the slack adjuster, thus twisting the brake camshaft. This
turns the s-cam forcing the brake shoes away from one another and presses them
against the inside of the brake drum.
Which of the following makes the total stopping distance for air brakes longer than
that for hydraulic brakes? - ANSWERBrake lag distance.
Explanation:
With air brakes there is an added delay or Brake Lag. This is the time required for
the brakes to work after the brake pedal is pushed. With hydraulic brake, the brakes
work instantly. With air brakes it takes a little time, one half second or more, for the
air to flow through the lines to the brakes.
The brake system that applies and releases the brakes when the driver uses the
brake pedal is the: - ANSWERService brake system.
Explanation:
The service brake system applies and releases the brakes when you use the brake
pedal during normal driving.
To make an emergency stop with air brakes, using the stab braking method, you
should: - ANSWERBrake as hard as you can, get off the brakes when the wheels
lock, get back on the brakes when the wheels start rolling again.
Explanation:
Stab braking means that you: apply your brakes all the way, and release brakes
when wheels lock up. As soon as the wheels start rolling, apply the brakes fully
again.
Brake lag distance at 55 mph is _____ feet - ANSWER32
Explanation:
The air brake lag distance at 55 mph on dry pavement adds about 32 feet.
, If your vehicle has an alcohol evaporator, it is there to: - ANSWERReduce the risk of
ice in air brake valves in cold weather.
Explanation:
Some air brake systems have an alcohol evaporator to put alcohol into the air
system. This helps to reduce the risk of ice in air brake valves and other parts during
cold weather. Daily air tank drainage is still needed to get rid of water and oil.
What can legally hold a parking or emergency brake in position for a truck, truck
tractor or bus? - ANSWERSpring pressure
Explanation:
All trucks, truck tractors, and buses must be equipped with emergency brakes and
parking brakes. They must be held on by mechanical force because air pressure can
eventually leak away. Spring brakes are usually used to meet these needs.
The braking power of the spring brakes: - ANSWERDepends on the adjustment of
the service brakes.
Explanation:
The braking power of spring brakes depends on the brakes being in adjustment. If
the brakes are not adjusted properly, neither the regular brakes nor the
emergency/parking brakes will work right.
Which of the following should you do before leaving your vehicle unattended? -
ANSWERSet the parking brakes.
Remove the keys.
Chock the wheels.
Explanation:
Never leave your vehicle unattended without applying the parking brakes or chocking
the wheels. Your vehicle might roll away and cause injury and damage
Under which conditions are front wheel brakes good? - ANSWERall weather
conditions
Explanation:
Front wheel brakes have been shown to be ideal under all weather and driving
conditions. Front wheel braking is unlikely to cause a skid even on icy roads.
If the air tanks are not drained, - ANSWERyour brakes may fail because of water
freezing.
Explanation:
Compressed air usually has some water and some compressor oil in it, which is bad
for the air brake system. For example, the water can freeze in cold weather and
cause brake failure.
An antilock braking system (ABS) - ANSWERactivates when your wheels are about
to lock up.
Explanation:
ABS is a computerized system that keeps your wheels from locking up during hard
brake applications.
Which of the following can cause brakes to fade or fail? - ANSWERExcessive use of
the service brakes
ANSWERS 100% CORRECT!!
Oil and water usually collect in compressed air tanks. If you do not have an
automatic tank drain, when should you drain the air tanks? - ANSWERAfter every
working day
EXPLANATION:
If your vehicle does not have automatic air tank drains, drain your air tanks at the
end of each working day to remove moisture and oil. Otherwise, the brakes could
fail.
What is the S-cam used for? - ANSWERTo apply the brakes.
Explanation:
When you push the brake pedal, air is let into each brake chamber. Air pressure
pushes the rod out, moving the slack adjuster, thus twisting the brake camshaft. This
turns the s-cam forcing the brake shoes away from one another and presses them
against the inside of the brake drum.
Which of the following makes the total stopping distance for air brakes longer than
that for hydraulic brakes? - ANSWERBrake lag distance.
Explanation:
With air brakes there is an added delay or Brake Lag. This is the time required for
the brakes to work after the brake pedal is pushed. With hydraulic brake, the brakes
work instantly. With air brakes it takes a little time, one half second or more, for the
air to flow through the lines to the brakes.
The brake system that applies and releases the brakes when the driver uses the
brake pedal is the: - ANSWERService brake system.
Explanation:
The service brake system applies and releases the brakes when you use the brake
pedal during normal driving.
To make an emergency stop with air brakes, using the stab braking method, you
should: - ANSWERBrake as hard as you can, get off the brakes when the wheels
lock, get back on the brakes when the wheels start rolling again.
Explanation:
Stab braking means that you: apply your brakes all the way, and release brakes
when wheels lock up. As soon as the wheels start rolling, apply the brakes fully
again.
Brake lag distance at 55 mph is _____ feet - ANSWER32
Explanation:
The air brake lag distance at 55 mph on dry pavement adds about 32 feet.
, If your vehicle has an alcohol evaporator, it is there to: - ANSWERReduce the risk of
ice in air brake valves in cold weather.
Explanation:
Some air brake systems have an alcohol evaporator to put alcohol into the air
system. This helps to reduce the risk of ice in air brake valves and other parts during
cold weather. Daily air tank drainage is still needed to get rid of water and oil.
What can legally hold a parking or emergency brake in position for a truck, truck
tractor or bus? - ANSWERSpring pressure
Explanation:
All trucks, truck tractors, and buses must be equipped with emergency brakes and
parking brakes. They must be held on by mechanical force because air pressure can
eventually leak away. Spring brakes are usually used to meet these needs.
The braking power of the spring brakes: - ANSWERDepends on the adjustment of
the service brakes.
Explanation:
The braking power of spring brakes depends on the brakes being in adjustment. If
the brakes are not adjusted properly, neither the regular brakes nor the
emergency/parking brakes will work right.
Which of the following should you do before leaving your vehicle unattended? -
ANSWERSet the parking brakes.
Remove the keys.
Chock the wheels.
Explanation:
Never leave your vehicle unattended without applying the parking brakes or chocking
the wheels. Your vehicle might roll away and cause injury and damage
Under which conditions are front wheel brakes good? - ANSWERall weather
conditions
Explanation:
Front wheel brakes have been shown to be ideal under all weather and driving
conditions. Front wheel braking is unlikely to cause a skid even on icy roads.
If the air tanks are not drained, - ANSWERyour brakes may fail because of water
freezing.
Explanation:
Compressed air usually has some water and some compressor oil in it, which is bad
for the air brake system. For example, the water can freeze in cold weather and
cause brake failure.
An antilock braking system (ABS) - ANSWERactivates when your wheels are about
to lock up.
Explanation:
ABS is a computerized system that keeps your wheels from locking up during hard
brake applications.
Which of the following can cause brakes to fade or fail? - ANSWERExcessive use of
the service brakes
