Air Brakes

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This endorsement is required for driving a vehicle with air brakes. To receive this endorsement, applicants must pass a written..

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 three or four answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Connecticut 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:

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.

Before starting down a hill, be sure to:

Explanation
Before starting down a hill, be sure to switch into a low gear. Gravity will increase your vehicle's speed as you travel downhill.

What color are ABS malfunction lamps?

Explanation
Vehicles with Anti-Lock Braking Systems (ABS) have yellow malfunction lamps.

A dual air brake system:

Explanation
A dual air brake system has two separate air brake systems that use a single set of brake controls. One system typically operates the regular brakes on the rear axle or axles. The other system operates the regular brakes on the front axle.

Brake fade is a result of:

Explanation
If brakes are overused, they can become too hot. This overheating causes them to fade, making them less effective at slowing the vehicle.

Water and compressor oil are usually found in the compressed air within an air brake system. Water and compressor oil:

Explanation
Compressed air in an air brake system usually contains a certain amount of water and compressor oil. The water and oil can damage the brakes if left to accumulate in the system. Manually operated air tank drains must be opened daily to remove this build-up.
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