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The air brakes endorsement applies to applicants who wish to drive a vehicle with air brakes in Class A, B, or C CDL. To drive a vehicle with air brakes, you must pass the air brake component of the California CDL knowledge test. The CA CDL air brakes test consists of 25 questions, and you'll need at least 20 correct answers to pass (80%). The test covers the information found in the air brakes section of the California CDL Manual. Take this CA CDL practice test now to prepare for the actual air brakes test!
1. If the spring brakes do not release when you push the trailer air supply control, you should:
check the air line connections.
rev or lug the engine.
check the electrical cables.
2. The Johnson bar is a valve that:
is installed in the first tank the air compressor pumps air to.
reduces the braking pressure to a safe level.
works the trailer brakes.
3. If the low pressure warning signal doesn't work:
this could cause sudden emergency braking in a single-circuit air system.
you could lose air pressure and you would know it.
None of the above.
4. To use the controlled braking method in an emergency, you should:
apply your brakes all the way, and release the brakes when the wheels lock up.
apply the brakes when the wheels lock up.
apply the brakes as hard as you can without locking the wheels.
5. When backing a trailer, turn the wheel right to make the cab go ________ and the trailer go ________.
right; left
left; left
left; right
6. Excessive use of the service brakes results in overheating. Too much heat can:
cause the brakes to grab.
cause the brakes apply unevenly.
make the brakes stop working.
7. The braking power of the spring brakes:
is not affected by the air pressure level.
is not affected by the condition of the service brakes.
depends on the brakes being in adjustment.
8. The one-way check valve:
supplies air to the trailer air tanks.
keeps your wheels from locking up when you brake hard.
keeps air from going out if the air compressor develops a leak.
9. How do you check that spring brakes come on automatically?
On a tractor-trailer combination vehicle, continue to step on and off the brake pedal until the tractor protection valve and the parking brake valve close.
Continue to step on and off the brake pedal until the air pressure falls to the manufacturer’s specification.
All of the above.
10. _________ must have a low air pressure warning signal.
All vehicles with air brakes
Vehicles with air brakes built after 2010
Vehicles with air brakes built after 2005
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CA CDL Air Brakes Test

Number of questions: 25
Correct answers to pass:20
Passing score:80%
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