Air Brakes
This endorsement is required for driving a vehicle with air brakes. To receive this endorsement, applicants must pass a written test. The test consists of 25 multiple choice questions. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Commonwealth of Pennsylvania Commercial Driver’s Manual. 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. During an applied leakage test, the maximum leakage rate for a double combination vehicle is:
Explanation
It is important to know the maximum air loss rate that is safe for your specific vehicle. A double combination vehicle should have a leakage rate no higher than 4 psi in a minute during an applied leakage test.
14. Most heavy-duty vehicles use ____ air brake systems.
Explanation
The majority of heavy-duty vehicles are equipped with dual air brake systems.
15. To use the stab braking method in an emergency situation, you should:
Explanation
The stab braking method for emergency stops involves fully applying the brakes until they lock up. The brakes are then released until the wheels start rolling, then the process is repeated.
16. A low air pressure warning signal should activate:
Explanation
In an air brake system, a low air pressure warning signal must come on if air pressure in the tanks falls below 60 psi. This warning signal may come in the form of a light, a buzzer, or a wig wag.
17. In a dual air brake system, a leak in one system:
Explanation
A dual air brake system is made up of two separate air brake systems. If there is an air leak in one system, it may not affect the other.
18. Vehicles with dual air brake systems:
Explanation
