Air Brakes
Directions
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. Each question has four answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Indiana Commercial Driver License Manual. Questions come from the chapter covering: Air Brakes. The Air Brakes endorsement may be used with the Class A, B or C CDL.
Passing grade:
If the spring brakes are activated, you should never:
Explanation
Never apply the brake pedal if your spring breaks are activated. Brakes can be damaged if they are subject to both springs and air pressure.
If the spring brakes are on, you should:
Explanation
You should not apply the brake pedal if the spring brakes are activated. The brakes could be damaged if they are subjected to the force of air pressure and the springs at the same time.
When only the tractor is equipped with an Anti-Lock Braking System (ABS):
Explanation
If a tractor is equipped with an Anti-Lock Braking System (ABS) but the trailer is not, the risk of jackknifing will be reduced and the driver should still be able to maintain steering control. If only the trailer is equipped with ABS, it is less likely that the trailer will swing out to one side.
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.
How is the parking brake released?
Explanation
In vehicles with air brakes, the parking brake is controlled by a knob. The knob is pulled out to apply the brakes, and pushed in to release them.
In a dual air brake system:
Explanation
