CDL Air Brakes Endorsement I Practice

1.

Why must air tanks be drained?

A.

To drain all the air out of the tank.
B.

To drain moisture and oil out of the tank.
C.

To keep anyone from moving the vehicle

Correct Answer
B. To drain moisture and oil out of the tank.

Explanation
Air tanks must be drained to remove moisture and oil that can accumulate inside the tank. Moisture and oil can enter the tank through the air compressor and can cause damage to the system if not removed. Draining the tank regularly helps to prevent corrosion, maintain the efficiency of the system, and ensure proper functioning of the air brakes.

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2.

What is a supply pressure gauge used for?

A.

To tell you how much diesel is in the vehicle.
B.

To tell you how much water is in the air tank.
C.

To tell you how much air is in the air tank.

Correct Answer
C. To tell you how much air is in the air tank.

Explanation
A supply pressure gauge is used to measure the amount of air in the air tank. This is important information for various applications, such as in pneumatic systems or air brakes, where the pressure level needs to be monitored to ensure optimal functioning. It helps in determining if the air tank has enough pressure for the intended use or if it needs to be refilled.

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3.

All vehicles with air brakes must have a low air pressure warning signal.

A.

True
B.

False

Correct Answer
A. True

Explanation
All vehicles with air brakes must have a low air pressure warning signal because it is crucial for the safety of the vehicle and its passengers. The low air pressure warning signal alerts the driver when the air pressure in the braking system is dangerously low. This warning signal is necessary to prevent brake failure and ensure that the vehicle can be safely stopped in case of an emergency. Without this warning signal, the driver may not be aware of the low air pressure and could potentially experience a brake failure, leading to a dangerous situation on the road. Therefore, it is essential for all vehicles with air brakes to have a low air pressure warning signal.

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4.

What are spring brakes?

A.

Brakes used for parking
B.

If the air brakes leak down, springs press the brakes on to stop the vehicle.
C.

The spring on the brake pedal.

Correct Answer
B. If the air brakes leak down, springs press the brakes on to stop the vehicle.

Explanation
Spring brakes are a type of brakes used for parking in vehicles. In the event that the air brakes leak down, springs are designed to press the brakes on and stop the vehicle. This safety feature ensures that even if there is a failure in the air brake system, the vehicle can still be brought to a halt.

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5.

Front wheel brakes are good under all conditions.

A.

True
B.

False

Correct Answer
A. True

Explanation
Front wheel brakes are good under all conditions because they provide better stability and control while braking. When the brakes are applied, the weight of the vehicle shifts forward, putting more load on the front wheels. This increased load on the front wheels allows for better traction and braking performance. Additionally, front wheel brakes help to prevent the vehicle from skidding or spinning out of control during sudden stops or emergency braking situations. Therefore, front wheel brakes are generally considered to be more effective and reliable in most driving conditions.

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6.

When you put your brakes on the air brake system works with an electric switch, by air pressure to turn on the brake lights.

A.

True
B.

False

Correct Answer
A. True

Explanation
When you put your brakes on, the air brake system in your vehicle activates an electric switch that uses air pressure to turn on the brake lights. This is a true statement because air brakes are commonly used in larger vehicles such as trucks and buses, and they rely on compressed air to activate the braking system. When the brakes are applied, the air pressure is released, which triggers the electric switch and illuminates the brake lights, indicating to other drivers that the vehicle is slowing down or stopping.

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7.

What do air brakes use to make the brakes work?

A.

Compressed gas
B.

Compressed oil
C.

Compressed air

Correct Answer
C. Compressed air

Explanation
Air brakes use compressed air to make the brakes work. Compressed air is stored in a reservoir and when the brake pedal is pressed, the compressed air is released into the brake system. This causes the brake chambers to expand, applying pressure to the brake shoes or pads, which then press against the brake drums or rotors, creating friction and slowing down or stopping the vehicle. Compressed air is an effective and reliable method for operating air brakes in heavy vehicles such as trucks and buses.

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8.

Air brakes are really three different braking systems: service brake, parking brake and emergency brake.

A.

True
B.

False

Correct Answer
A. True

Explanation
Air brakes in vehicles are indeed composed of three distinct braking systems: the service brake, the parking brake, and the emergency brake. The service brake is used for regular stopping and slowing down of the vehicle, while the parking brake is used to keep the vehicle stationary when parked. The emergency brake, on the other hand, is a backup system that can be used in case of a failure in the service brake. Therefore, the statement that air brakes consist of these three braking systems is true.

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9.

The service brake applies and releases:

A.

The parking brake when you use the parking brake control.
B.

The brake when you use the brake pedal during normal driving.
C.

In the event of an emergency. In the event of an emergency. In the event of an emergency.

Correct Answer
B. The brake when you use the brake pedal during normal driving.

Explanation
The correct answer is "The brake when you use the brake pedal during normal driving." This means that when you press the brake pedal while driving, the service brake applies and releases to slow down or stop the vehicle. This is the normal function of the brake pedal during regular driving situations.

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10.

The parking brake applies and releases:

A.

The brake pedal during normal driving.
B.

In the event of an emergency.
C.

The parking brakes when you use the parking brake control.

Correct Answer
C. The parking brakes when you use the parking brake control.

Explanation
The correct answer is "The parking brakes when you use the parking brake control." This means that the parking brake is applied and released when you specifically use the parking brake control. It is not applied or released by the brake pedal during normal driving or in the event of an emergency. This indicates that the parking brake is a separate mechanism that is controlled independently from the regular braking system.

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11.

The emergency brake system:

A.

Uses parts of the service and parking brake system to stop the vehicle in the event of a brake system failure.
B.

Uses the service brake to stop the vehicle in the event of a brake system failure.
C.

Uses the parking brake to stop the vehicle in the event of a brake system failure.

Correct Answer
A. Uses parts of the service and parking brake system to stop the vehicle in the event of a brake system failure.

Explanation
The emergency brake system utilizes both the service brake and the parking brake components to bring the vehicle to a halt in case of a brake system failure. This means that if the primary brake system fails, the emergency brake system can still be used to stop the vehicle safely. By combining the functionality of both the service brake and the parking brake, the emergency brake system provides an additional layer of safety and ensures that the vehicle can be brought to a stop even in the event of a brake system failure.

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12.

The governor controls when the air compressor will pump into the air storage tanks.

A.

True
B.

False

Correct Answer
A. True

Explanation
The statement is true because the governor is responsible for regulating the operation of the air compressor. It determines when the compressor will pump air into the air storage tanks based on the pressure levels in the tanks. The governor ensures that the tanks maintain a certain level of air pressure, preventing them from becoming overfilled or depleted. Therefore, the governor plays a crucial role in controlling the pumping of air into the storage tanks.

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13.

The air storage tanks are used to hold compressed air.

A.

True
B.

False

Correct Answer
A. True

Explanation
Air storage tanks are indeed used to hold compressed air. These tanks are designed to store and release compressed air as needed for various applications, such as pneumatic tools, industrial processes, and air-powered machinery. They help maintain a steady and reliable supply of compressed air, allowing for efficient operation and reducing the strain on air compressors.

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14.

When you put on the brakes by pushing down the brake pedal:

A.

The air pressure is reduced to the brake pads.
B.

Air pressure is applied to the brake pads.
C.

Compressed air is let go out of the system. Compressed air is let go out of the system. Compressed air is let go out of the system.

Correct Answer
B. Air pressure is applied to the brake pads.

Explanation
When you put on the brakes by pushing down the brake pedal, air pressure is applied to the brake pads. This is because the brake pedal is connected to the brake system, which includes a master cylinder. When you push down the brake pedal, it activates the master cylinder, which in turn applies hydraulic pressure to the brake fluid. This hydraulic pressure is then transmitted to the brake calipers or wheel cylinders, which apply pressure to the brake pads or shoes. The pressure applied to the brake pads creates friction against the rotors or drums, causing the vehicle to slow down or stop.

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15.

The S-cam forces the brake shoes away from one another and presses them against the inside of the brake drum. It is called the S-cam because:

A.

It is shaped like the letter Z.
B.

It is shaped like the letter N.
C.

It is shaped like the letter S.

Correct Answer
C. It is shaped like the letter S.

Explanation
The S-cam is called so because it is shaped like the letter S.

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