Air Brakes Test 1

Emergency stab braking is when you:

Break as hard as you can, release the brakes when the wheels lock, and put on the brakes again when the wheels start rolling

If air pressure does NOT build up to normal within the correct amount of time, then:

Your air pressure may drop too low during driving, requiring an emergency stop

Which of these is NOT a proper time to apply the parking brakes?

If the brakes are very hot (e.g., after just coming down a steep grade)

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

Expansion of the brake drums

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

Under normal conditions, in order to engage the parking brakes the driver must first:

Let the air out of the air brake system

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

Brake lag

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

Can steer and so your vehicle stays in a straight line

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

The driver must be able to see a warning before air pressure in the service air tanks fall below __ psi:

60

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

Level ground with the parking brake, then apply the service brakes

A straight truck or a bus air brake system should not leak at a rate of more than __ psi per minute with the engine off and the brakes released:

2

The air pressure compressor governer controls:

When air is pumped into the air brakes

The parking or emergency brake on a heavy vehicle can only be held in position by something that cannot leak away, like:

Spring pressure

The brake pedal in air brake system:

Controls the air pressure applied to put on the brakes

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 cause the brakes to fall

The brake system that applies and releases the brakes when the driver uses the brake pedal is the __ brake system?

Service

Before driving a truck or bus with the dual air-brake system, the pressure in each system should be at least __ psi:

100

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

Stop right away and safety park. Continue only after the system is fixed

How should you check that your service brakes are working properly?

Wait for normal air pressure, release the parking brake, move the truck forward slowly, and apply the brake firmly using the brake pedal