Air Brakes
This endorsement is required for driving a vehicle with air brakes. To receive this endorsement, applicants must pass a test. The test consists of 25 multiple choice questions. Each question has four answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Texas Commercial Motor Vehicle Drivers Handbook. Questions come from chapters covering: Air Brakes. The Air Brakes endorsement may be used with the Class A, B or C CDL.
Number of Question
Passing Score
13. To ensure normal stopping power, drivers of vehicles equipped with a front brake limiting valve should:
Explanation
Some pre-1975 vehicles have a front brake limiting valve, which has "normal" and "slippery" settings. The idea behind these valves was to limit the air pressure available to the front brakes when driving on slippery surfaces, and thereby reduce the danger of a front-wheel skid. Studies have found that this is not actually a concern, so if your vehicle has a front brake limiting valve, leave it in the "normal" position.
14. To stop in a vehicle that uses air brakes, the driver should:
Explanation
To make a normal stop in a vehicle with air brakes, push the brake pedal down. The harder the pedal is pressed, the more air pressure is released.
15. Pressing and releasing a brake pedal unnecessarily can:
Explanation
In an air brake system, pressing and releasing the brake pedal unnecessarily can release air from the braking system faster than the compressor can replace it.
16. During a static leakage test, the maximum leakage rate for a single vehicle with air brakes is ____ in one minute.
Explanation
When performing a static leakage test on a single vehicle with air brakes, the leakage rate should be no more than 2 psi in a minute. If air leaks from the air brake system at a quicker rate, the vehicle should not be driven because something likely needs to be repaired.
17. During an applied leakage test, the maximum leakage rate for a single vehicle with air brakes is:
Explanation
It is important to know the maximum air loss rate that is safe for your specific vehicle. A single vehicle with air brakes should have a leakage rate no higher than 3 psi in a minute during an applied leakage test.
18. Truck tractors with air brakes that were built on or after March 1, 1997 are equipped with:
Explanation
