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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 Washington CDL knowledge test. The WA 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 Washington CDL Manual. Take this WA CDL practice test now to prepare for the actual air brakes test!
1. Passive railroad crossings:
should never be crossed using a CMV.
have at least one traffic control device.
do not have traffic control devices.
2. You should check air pressure and temperature gauges:
at the end of each trip.
as often as is practical.
at the beginning of each trip.
3. How do you check that spring brakes come on automatically?
Continue to step on and off the brake pedal until the air pressure falls to the manufacturer’s specification.
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.
All of the above.
4. The __________ keeps air from going out if the air compressor develops a leak.
emergency relay valve
one-way check valve
tractor protection valve
5. Empty trucks have the best braking. True or False?
It depends on the cargo.
6. 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.
7. Your vehicle has a dual air brake system. If one air system is very low on pressure, you should:
call your dispatcher or supervisor for instructions.
reduce your speed and check the low air pressure warning signal for the other system regularly.
bring the vehicle to a safe stop, and have the air brakes system fixed.
8. Which of the following statements is true?
Poor cargo ventilation is a common cause of fire.
Carrying a properly charged and rated fire extinguisher will help prevent fires.
There is no way that short circuits due to damaged insulation can cause a vehicle fire.
9. The safety relief valve is usually set to open at ____ psi.
10. Air tank drains:
are used to remove water and oil from the air tanks.
should not be used in wet weather.
protect the tanks and the rest of the system from too much pressure.
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WA CDL Air Brakes Test

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