Air Brakes Test 3

If your truck or bus 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

During normal driving, spring brakes are usually held back by:

Air pressure

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

S-cam drum

Parking or emergency brakes of trucks and buses can be legally held on by __ pressure:

Spring

The air compressor governor controls:

When air pumped into the air tanks

A supply pressure gauge tells you how much pressure is in the:

Air tanks

When you apply the brakes, the brake shoes/linings are pressed against the:

Brake drum

Why drain water from compressed air trucks?

Water can freeze in cold weather and cause brake failure

Some air brake systems have an alcohol evaporator. What may happen if you don't keep the unit filled with alcohol?

Ice may form in the air storage tanks and cost the brakes to fail

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

Stop and safely park as soon as possible

Repeatedly pressing and releasing (fanning) the brake pedal may result in:

The loss of brake air pressure

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

Never

If your vehicle has an alcohol evaporator, every day during cold weather, you should:

Check and fill the alcohol level

You should know that your brakes are fading when:

You have to push harder on the break pedals to control your speed on a downgrade

Your truck has a properly functioning dual air brake system and minimum size air tanks. The air pressure should build from 85 to 100 psi within __ seconds:

45

Your truck or bus has a dual air brake system. If a low air pressure warning comes on for only one system, what should you do?

Stop and safely park. Continue only after the system is fixed.

It is not safe to drive a vehicle that has brake drums (or discs) with cracks or that are thinner than the manufacturers specification, generally, this will be __ inch:

1/4

Air braking takes more time than hydraulic breaking because air:

Takes more time to flow through the lines than hydraulic fluid

Total stopping distance for vehicle with air brakes is longer than that for vehicle with hydraulic brakes due to __ distance

Brake lag

If you must make an emergency stop, brake, so you:

Can steer and so your vehicle stays in a straight line

Emergency controlled braking is when you:

Apply the brake as hard as you can without locking the wheels

When is it OK to leave your truck unattended without applying the parking brake or chocking the wheels?

Never

The use of air brakes on a downgrade is only a supplement to the:

Braking effect of the engine

The proper method of braking when going down long and/or steep grades after selecting the proper gear is to brake until your speed is about __ miles per hours below your “safe” speed, and then release your brakes.

5

You are on a steep downgrade, and have reached your “safe” speed of 40 MPH. You would apply the service brakes until speed drops to __ MPH?

35