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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. Supply pressure gauges tell you:
how much pressure is in the air tanks.
how much air pressure you are applying to the brakes.
when the pressure in the system drops below 60 psi.
when the air pressure in the tanks falls below 60 psi.
2. If the air tanks are not drained:
your speed must be reduced to 5 MPH below your “safe” speed.
the air pressure in the tanks is reduced.
the water can freeze in cold weather and cause brake failure.
the spring brakes will come on.
3. Brake lag is:
the distance your vehicle will travel, in ideal conditions, while you are braking.
the amount of air pressure required to stop the vehicle.
the distance your vehicle will continue to travel, in ideal conditions, before you hit the brakes.
the time required for the air brakes to work after the brake pedal is pushed.
4. An Anti-lock Braking System (ABS):
lets you drive faster.
keeps your wheels from locking up when you brake hard.
increases your normal braking capability.
always shortens your stopping distance.
5. In vehicles with air brakes, the air compressor governor:
controls how much air the air compressor will pump into the air storage tanks.
controls when the air storage tanks will pump air into the air compressor.
controls when the air compressor will pump air into the air storage tanks.
None of the above.
6. Most heavy vehicles require ________ change gears.
single clutching
double shifting
triple shifting
double clutching
7. You should NOT use the parking brakes if:
the brakes are too dry.
the brakes are cold.
the brakes are very hot.
All of the above.
8. How many reflective triangles/emergency reflectors should you carry?
9. Air brakes are 3 different braking systems: service brake, parking brake, and _______ brake.
air storage brake
10. If are being followed closely, you should:
change lanes quickly.
flash your brake lights.
increase your following distance.
decrease your following distance.
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WI CDL Air Brakes Test

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