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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 Illinois CDL knowledge test. The IL 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 Illinois CDL Manual. Take this IL CDL practice test now to prepare for the actual air brakes test!
1.
Your mirrors should be adjusted so that:
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more than half of the mirror shows the vehicle.
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the rear of the vehicle is visible in the mirror.
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a part of the vehicle is visible in the mirror.
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no part of the vehicle is visible in the mirror.
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2.
In air-operated disc brakes, the pressure of the ______ on the ______ turns a "power screw".
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brake camshaft; tie rod
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slack adjuster; tie rod
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slack adjuster; cam roller
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brake chamber; slack adjuster
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3.
To check that spring brakes come on automatically, the first thing to do is to:
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continue to step on and off the brake pedal until the air pressure falls to the manufacturer’s specification.
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turn off the engine, release the parking brake and time the air pressure drop.
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release the parking brake, move the vehicle forward slowly, and apply the brakes firmly.
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All of the above.
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4.
If your vehicle is equipped with air brakes, loss of air pressure in the
emergency line causes:
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the trailer emergency brakes to come on.
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the trailer spring brakes to come on.
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the speed of your vehicle to increase.
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All of the above.
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5.
Some vehicles have a separate air tank which can be used to:
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release the spring brakes.
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unload cargo or passengers.
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hold the vehicle or combination of vehicles stationary.
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turn on the 4-way emergency flashers.
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6.
Why should you check your mirrors regularly to know where other vehicles are around you?
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To move out of their way if they want to get past.
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To flash the brake lights if you are being tailgated.
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To better assess your own speed.
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To know whether you can make a quick lane change in an emergency.
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7.
If your vehicle catches fire, you should pull over:
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in an open area.
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near other vehicles.
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near trees.
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at a service station.
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8.
If your brakes fail while you are driving on a downgrade, you should:
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take the least hazardous escape route you can.
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immediately start looking outside your vehicle for something to stop it.
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use an escape ramp if it's available.
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All of the above.
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9.
What is a dual air brake system?
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2 separate air brake systems: one system operates the left brakes, the other system operates the right brakes.
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2 separate air brake systems: one system operates the front brakes, the other system operates the rear brakes.
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2 separate air brake systems: one system for daytime driving, the other system for nighttime driving.
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None of the above.
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10.
If your vehicle has an alcohol evaporator, every day during cold weather, you should:
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check the alcohol container and fill up as necessary.
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fill it up with oil to prevent the pipes from freezing.
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fill it up with oil to prevent alcohol from freezing.
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ensure that compressed air usually has some water and some compressor oil in it.
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