Air Brake System Quiz 3

The amount of pressure that is shown by the application pressure gauge is ______.

• The amount available inside the tanks

• The amount being vented into the atmosphere.

• The amount that you are applying to the brakes.

Answer explanation

The amount that you are applying to the brakes.

Why do we need an S-cam?

• Controls how much air goes into each of the brake chambers.

• Frees the wheels by separating the brake shoes from the brake drum.

• Pushes the brake shoe against the inside of the brake drum.

Answer explanation

The S-cam pushes the brake shoe against the inside of the brake drum.

Which of the following types of foundation brakes are commonly found on air brake vehicles?

• Air-over-hydraulic brakes.

• S-cam drum brakes.

• Wedge brakes.

• Disc brakes

Answer explanation

S-cam drum brakes are commonly found on air brake vehicles, making them the correct choice among the options provided.

The modulating control valve allows you to control ___.

• Steering axle brakes.

• Rear brakes.

• Spring brakes.

• Air brakes.

Answer explanation

The modulating control valve allows you to control air brakes, making it the correct choice among the options provided.

How thick must the lining of the drum be under federal regulations on air brakes?

• ⅛ inch

• ¼ inch

• ⅓ inch

• ½ inch

Answer explanation

The correct thickness of the lining of the drum under federal regulations on air brakes is ¼ inch.

What is the function of the stop light switch?

• The brake light will come on when you press the pedal.

• It turns on when your brakes are having issues. You need to repair it before driving again.

• It reminds the driver to take a break or rest after a long drive.

• Turn it on to prevent the vehicle from rolling away if the parking brakes fail.

Answer explanation

The brake light will come on when you press the pedal.

When testing for an air leak. You should turn off the engine and hold the brake for 1 minute: after the initial drop, the air pressure should not drop more than ____ psi in one minute.

• 5

• 12

• 3

• 10

Answer explanation

When testing for an air leak, the air pressure should not drop more than 3 psi in one minute. This ensures the system is holding pressure properly.

Which of the following are true regarding spring brakes?

Answer explanation

Spring brakes are used in air brake systems to stop a vehicle in case of air pressure loss. They are applied automatically when air pressure drops below a certain level, ensuring safety.

The use of air brakes on a long and steep downhill is just to provide extra braking to help the ____.

• Braking power of the steering axle.

• Braking power of the rear trailer axle

• The use of engine braking.

• All of the above

Answer explanation

The use of air brakes on a long and steep downhill is just to provide extra braking to help the braking power of the steering axle, braking power of the rear trailer axle, and the use of engine braking.

Air brakes use ____ to make brakes work.

• Nitrogen.

• Hydraulic fluid.

• Pressurized air.

• Hydrogen.

Answer explanation

Air brakes use pressurized air to make brakes work, not nitrogen, hydraulic fluid, or hydrogen.