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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 Texas CDL knowledge test. The TX 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 Texas CDL Manual. Take this TX CDL practice test now to prepare for the actual air brakes test!
1. When going down grades, you should:
put the transmission in Neutral.
shift up.
rely solely on engine braking to reduce your speed.
downshift to a lower gear.
2. Under a pressurized system, the radiator cap:
should be removed when the coolant is hot.
should always be cool.
should never be removed until the system has cooled.
should never be hot.
3. If you are driving a 30-foot vehicle at 55 mph, you should leave at least _____ between you and the vehicle ahead.
3 seconds
4 seconds
2 seconds
5 seconds
4. Parking brakes are:
not required on commercial vehicles with air brakes.
not required on trailers.
not required on buses.
required on all vehicles.
5. The application pressure gauge shows:
how much pressure the relay valves should send to the trailer brakes.
how much air pressure you are applying to the brakes.
how much pressure is in the air tanks.
All of the above.
6. To control your speed on a downgrade, you should:
fully apply the brakes.
use engine braking.
use controlled braking.
coast in neutral.
7. Vehicles with air brake systems take longer to come to a complete stop than vehicles with hydraulic brakes because of:
brake lag.
tire pressure.
reaction distance.
brake fading.
8. With air brake vehicles, you should use the parking brakes:
only if your vehicle is equipped with ABS.
whenever you leave the vehicle unattended.
as little as possible.
only during the vehicle inspection test.
9. If your tires are hot, you should NOT:
drive until you correct the cause of the overheating.
stop to let the tires cool down.
let air out of the tires so the pressure goes back to normal.
once the tires have cooled down, make another stop to check the tires.
10. Vehicles with ABS have ______ ABS malfunction lamps on the instrument panel.
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TX CDL Air Brakes Test

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