Instructions

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.. Read More

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 25

Passing Score 20

1. The air pressure in a dual air brake system should build from 85 to 100 psi within:

Two minutes.

15 seconds.

10 minutes.

45 seconds.

When inspecting a vehicle with a dual air brake system, you should wait for air pressure to build from 85 to 100 psi in both the primary and secondary systems. This should take about 45 seconds.

2. Failing to drain the tanks in an air brake system can result in:

Water freezing and causing brake failure.

Squishy brakes.

Too much air collecting.

Too much fuel being carried.

In an air brake system, the air storage tanks must be drained to remove accumulated water and compressor oil. Failing to do this can cause damage. For example, water that has built up in the system could freeze in cold weather and cause brake failure.

3. If the brake pads rub against the brake drums and create too much heat:

The brakes will stick.

The brakes will become extra sensitive.

The brakes may stop working.

The air compressor will kick on to cool the brakes.

Brakes heat up with use. If they are overused and become too hot, expansion and chemical changes will make them less effective and eventually cause them to stop working altogether. This is known as "brake fade."

4. Vehicles with dual air brake systems:

Maintain full-capacity air pressure in the braking systems even when the vehicle is not running.

Maintain some air pressure in the braking systems when the vehicle is not running.

Must be run to build enough air pressure to brakes to operate properly.

Do not need time to build air pressure before a trip.

Before driving a vehicle with a dual air brake system, you must allow the air compressor time to build up at least 100 psi of air pressure in both the primary and secondary systems.

5. A vehicle equipped with an Anti-Lock Braking System (ABS) uses a ____ light to warn that the system is not working properly.

Green

Yellow

Orange

White

Anti-Lock Braking System (ABS) malfunction lamps are usually yellow. Even if the ABS isn't working properly, a driver will still have access to the vehicle's usual braking functions.

6. During a static leakage test, the maximum leakage rate for a triple combination vehicle with air brakes is ____ in a minute.

3 psi

5 psi

7 psi

9 psi

When performing a static leakage test on a triple combination vehicle with air brakes, the leakage rate should be no more than 5 psi in one 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.

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