Instructions

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.. Read More

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 25

Passing Score 20

13. During an applied leakage test, the maximum leakage rate for a double combination vehicle is:

10 psi in a minute.

8 psi in a minute.

6 psi in a minute.

4 psi in a minute.

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.

Single

Dual

Triple

Quad

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:

Apply the brakes completely until the wheels lock up, release the brakes until the wheels start rolling, then repeat the process.

Apply the brakes about halfway, but keep the wheels rolling.

Fully apply the brakes, let the wheels lock up, and hold the brake pedal down, keeping the wheels locked until the vehicle stops.

Apply the emergency brake.

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:

When tank pressure falls below 120 psi.

When tank pressure falls below 60 psi.

When tank pressure falls below 10 psi.

When tank pressure falls below 5 psi.

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:

Always means there are leaks in both systems.

May not affect the other system.

Is not something to worry about.

Will also affect the other system.

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:

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.

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