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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 Wisconsin CDL knowledge test. The WI 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 Wisconsin CDL Manual. Take this WI CDL practice test now to prepare for the actual air brakes test!
1.
To test the service brake:
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push the brake pedal firmly while going about 5 mph.
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push the brake pedal firmly while slowly moving backward.
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gently try to pull forward with the trailer parking brake on, then release the brake.
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shift your transmission to a low gear, pump the brake pedal three times, then hold it down for five seconds.
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2.
To perform an applied leakage test, the vehicle’s air pressure should be built up to maximum pressure. Check the air gauge to see that the air pressure should drop no more than:
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1 psi for single vehicles and 3 psi for a combination of 2 vehicles.
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3 psi for single vehicles and 4 psi for a combination of 2 vehicles.
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2 psi for single vehicles and 5 psi for a combination of 2 vehicles.
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5 psi for single vehicles and 6 psi for a combination of 2 vehicles.
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3.
The air tanks should be drained completely to remove:
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water and oil.
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the radiator cap.
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air.
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carbon monoxide.
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4.
Before driving a vehicle with a dual air brake system, you should allow time for the air compressor to build up a minimum of ____ pressure in both the primary and secondary systems.
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150 psi
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35 psi
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50 psi
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100 psi
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5.
You supply air to the trailer brake system by:
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pushing in the trailer air supply knob.
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pulling out the trailer air supply valve.
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plugging the electrical cord into the trailer.
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connecting the tractor service air line to the trailer service glad hand.
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6.
In vehicles with air brakes, the brake pedal:
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let the
air out of the spring brakes.
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controls the air pressure applied to the brakes.
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tells you how much pressure is in
the air tanks.
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pumps air into the air storage
tanks.
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7.
Empty trucks have the best braking. True or False?
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It depends on the cargo.
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False.
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It depends on the truck.
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True.
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8.
Emergency brakes must be held on by:
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dynamic pressure.
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hydraulic pressure.
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air pressure.
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mechanical force.
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9.
Front wheel braking is good:
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only in good weather.
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Never.
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under all conditions.
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only in wet conditions.
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10.
When driving in very hot weather, the heat will increase the chances of:
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loss of hydraulic pressure.
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tire failure.
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ABS malfunction.
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suspension system defects.
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