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. Each question has two, three or four possible answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Minnesota Commercial Driver’s Manual. Questions come from the chapters covering: Air Brakes and Combination Vehicles. The Air Brakes endorsement may be used with the Class A, B or C CDL.
Number of Question
Passing Score
13. When glad hands are coupled, the seals should be pressed together at a ____ angle.
Explanation
When coupling, be sure to couple the proper glad hands. When glad hands are connected, the seals should be pressed together at a 90-degree angle.
14. A shut-off valve:
Explanation
Shut-off valves are used in air supply lines to control the passage of air from one trailer to another. The rear shut-off valve should always be closed to prevent air from leaving the braking system.
15. When driving a combination rig, following distance should be:
Explanation
In comparison to driving a single vehicle, you should maintain an extended following distance when driving a combination rig. Combinations require longer stopping distances than smaller vehicles.
16. Before a vehicle with dual air brakes is driven, pressure of at least ____ should be built up in both braking systems.
Explanation
Before driving a vehicle with a dual air brake system, allow time for the air compressor to build up pressure of at least 100 psi in both the primary and secondary systems.
17. The most common type of foundation brake used is the:
Explanation
The most common type of foundation brake is an s-cam drum brake.
18. Brakes out of adjustment will:
Explanation
