Air Brakes - 4th Test (Chapter 5 in CDL Handbook)

Modern air brake systems combine three different systems. The systems are the service, parking, and ________ brake systems.

• Emergency

• Drum

• S-cam

• Disc

You should be able to see a warning before air pressure in the service tank falls below ______ psi.

• 60

• 80

• 100

• 120

The brake pedal in the air brake system:

• Controls the speed of the air compressor

• Controls need to be held down halfway during normal driving

• Controls the air pressure applied to the brakes

• Is connected to the slack adjusters by a series of rods and linkages

Air braking takes more time than hydraulic braking because air:

• Takes more time to flow through the lines than hydraulic fluid

• Takes more time to flow through the lines than hydraulic fluid

• Must travel through air line fittings

• Boost pressure the same way turbochargers boost engines

If your vehicle has an alcohol evaporator, it is there to:

• Help reduce the risk of ice in air brake valves in cold weather

• Eliminate the need for daily tank draining

• Boost tank pressure in cold weather

• Remove oil and water from the air tanks

If your truck has dual parking control valves, you can use pressure from a separate tank to:

• Release the spring emergency parking brakes to move a short distance

• Apply more brake pressure, if the main tank is getting low

• Stay parked twice as long with your service air pressure

• Balance the service brake system whenever you are parked

To check the free play of manual slack adjusters on S-cam brakes, you should park on:

• Level ground with the parking brake on; then apply the service brakes

• Level ground, chock the wheels and turn off the parking brakes

• Level ground and drain off air pressure before adjusting

• A slight grade, release parking brakes, apply the service brakes and check for vehicle movement

Of the choices below, the first thing to do when a low air pressure warning comes on is:

• Stop and safely park as soon as possible

• Shift to the next higher gear

• Open the air supply control valve

• Adjust the brake pedal for more travel

The air compressor governor controls:

• When the brake chambers release pressure

• Air pressure applied to the brakes

• When the air is pumped in the air tanks

• The speed of the air compressor

The braking power of the spring brakes:

• Is not affected by the condition of the spring brakes

• Can only be tested by highly trained brake service people

• Depends on whether the service brakes are in adjustment

• Increases when the service brakes are hot