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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. When you pull hard on a slack adjuster and it moves more than about _____ where the push rod attaches to it, the slack adjuster probably needs adjustment.
2 inches
1/2 inch
1 inch
2. Which of the following is NOT a reason for hydraulic brake failure?
Loss of hydraulic pressure
Stab braking
Brake fade on long hills
3. When you apply the brakes, the brake shoes and linings are pushed against:
the s-cam.
the inside of the brake drum.
slack adjusters.
4. The stop light switch:
warns you when the air supply pressure drops below 55 psi.
turns on the brake lights when you put on the air brakes.
tells you when you need to use your parking brake instead of the service brake.
5. Air tank drains:
are used to remove water and oil from the air tanks.
protect the tanks and the rest of the system from too much pressure.
should not be used in wet weather.
6. Axle weight is:
the weight transmitted to the ground by one axle or one set of axles.
the weight of all the axles added together.
the maximum safe weight your tires can carry at a specified pressure.
7. The ______ puts alcohol into the air system.
alcohol evaporator
alcohol tank drains
air tank drains
8. The use of brakes on a steep downgrade is:
the main braking factor.
much more effective than the engine braking effect.
a supplement to the braking effect of the engine.
9. If your vehicle is equipped with a front brake limiting valve, to ensure normal stopping power make sure the control is:
in the "normal" position.
in the "neutral" position.
in the "slippery" position.
10. A broken exhaust system:
poses no threat to the driver.
can let poisonous carbon monoxide to leak into the cab.
can improve fuel efficiency.
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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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