Air Brakes

The most common type of foundation brake found on heavy vehicles is the:

S-cam drum

The breaking power of the spring brakes:

Depends on the service brakes being in adjustment

Repeatedly partially increasing and pressing the brake pedal may result in:

A loss of brake air pressure

An air brake system is fully charged at what psi?

125

Excessive use of the service brakes results in overheating, which leads to:

Expansion of the Brake drums

If the air compressor should develop a leak, what keeps the air in the tanks?

The one-way check valve.

If the spring brakes are on, when should you push the brake pedal?

Never.

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

Level ground, chock the wheels and release the parking brakes.

The use of brakes on a long and steep downgrade under normal conditions is only a supplement to:

The braking effect of the engine.

The most important thing to do when a low air pressure warning comes on is:

Stop and safely park as soon as possible

The safety valve discharges automatically at the pressure of:

150 psi

If air pressure is not built up within the correct amount of time, then:

Air pressure may drop to a low point while driving, requiring an emergency stop.

It is not safe to drive to a vehicle that has brake drums with cracks that are longer than ___ of the width of the friction area.

1/2

The air compressor governor controls:

When air is pumped into the air tanks

The proper use of the brakes when going down a long steep grade after selecting a proper ear is to brake until your speed is about ____ below the posted speed and release your brakes

5 mphs

In ideal conditions, a truck or bus with air brakes going 55 mph would require the stopping distance of how many feet?

More than 300 feet.

The stop light switch:

Turns on the brake lights when you put on the air brakes.

To test air service brakes, you should:

Brake firmly while slowly moving forward.

If your truck has a dual air brake system, and one of the systems is low on pressure:

Either the front or rear brakes will not be fully functional