Air Brakes

Question 1

The stop light switch:

Answer 1

Turns on the brake lights to warn drivers behind you

Question 2

Truck and bus parking or emergency brakes must be heald on by:

Answer 2

Mechanical Force

Question 3

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

Answer 3

S-cam drum

Question 4

You are on a steep downgrade and have reached your “safe” speed of 40 mph. You would apply the service brake until you speed drops to ___

Answer 4

35 mph

Question 5

How should you check that the trailer brakes come on when air pressure in the system drops below a certain level?

Answer 5

Chock the wheels, release the parking brake, shut the engine off, and check for movement

Question 6

If your truck’s air compressor has its own oil supply, when should you first check the oil level?

Answer 6

Before Driving

Question 7

For air brake systems, the air compressor should start pumping at no lower than ___psi

Answer 7

85 psi

Question 8

You should know you brakes are fading when:

Answer 8

You have to push the brake pedal harder to control speed on a downgrade

Question 9

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

Answer 9

The loss of brake air pressure

Question 10

The air brake lag distance at 55 mph on dry pavement adds about ___feet to you stopping distance

Answer 10

32 ft

Question 11

In air brake vehicles, the parking brakes should be used:

Answer 11

Any time the vehicle is parked

Question 12

If the spring bakes are on, when should ypou push the brake pedal?

Answer 12

Never

Question 13

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

Answer 13

Either the front or rear brakes will not be fully operational

Question 14

The air loss rate for a straight truck or bus with the engine off and the brakes on should no be more than:

Answer 14

3 psi in one minute

Question 15

The brake pedal in an air brake system:

Answer 15

Controls the air pressure applied to put on the brakes

Question 16

The braking power of the spring brakes:

Answer 16

Depends on the service brakes being in adjustment

Question 17

The driver must be able to see a low air pressure warning which comes on before pressure in the service air tanks falls below___psi.

Answer 17

55 psi

Question 18

What is emergency control braking:

Answer 18

You apply the brakes as hard as you can without locking the wheels

Question 19

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

Answer 19

Release spring emergency/parking brakes to move a short distance

Question 20

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

Answer 20

Air pressure

Question 21

The parking or emergency brakes of trucks and buses can be legally heald on by ___ pressure

Answer 21

Spring

Question 22

The air compressor governor controls:

Answer 22

When air is pumped into the air storage tanks

Question 23

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

Answer 23

Air Tanks

Question 24

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

Answer 24

Brake Drum

Question 25

Why drain water from compressed air tanks?

Answer 25

Water can freeze in cold weather and cause brake failure

Question 26

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

Answer 26

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

Question 27

The (first) most important thing to do when low air pressure warning comes on is:

Answer 27

Stop and safely park as soon as possible

Question 28

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

Answer 28

Check and fill the alcohol level

Question 29

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

Answer 29

45 seconds

Question 30

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?

Answer 30

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

Question 31

It is not safe to drive a vehicle that has brake drums (or discs) with craks or that are thinner than manufacturer's specifications, generally this will be ___ inch.

Answer 31

1/4 inch

Question 32

Air braking takes more time than hydralic braking because air:

Answer 32

takes more time to flow through the lines than hydraulic fluid

Question 33

Total stopping distance for vehicles with brakes is longer than that for vehicles with hydralic brakes due to ___ distance

Answer 33

Brake Lag

Question 34

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

Answer 34

Can steer and you vehicle stays in a straight line

Question 35

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

Answer 35

Never

Question 36

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

Answer 36

Braking effect on the engine

Question 37

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

Answer 37

5 mph

Question 38

The S-cam:

Answer 38

Forces the brake shoes agaist the inside of the brake drum

Question 39

To test air service brakes, you should:

Answer 39

Brake firmly when slowly moving forwards

Question 40

If you dont have automatic tanks drains, how often should you drain the oil and water from the bottom of compressed air storage air tanks?

Answer 40

At the end of each day of driving

Question 41

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

Answer 41

When you brakes are very hot

Question 42

the brake system that applies and releases the brakes when the driver uses the brake pedal is the ___ brake system

Answer 42

Service

Question 43

For air brake systems in good condition, the air compressor should start pumping at about ___ psi.

Answer 43

100 psi

Question 44

Before driving a truck or bus with a dual brake system, the pressure in each system should be at least ____psi.

Answer 44

100 psi

Question 45

Modern air brake systems are three different systems combined together. They are the service, parking, and the ___ brakes.

Answer 45

Emergency

Question 46

The modulating control valve allows you to control the:

Answer 46

Spring Brakes

Question 47

Exessive heat in the brakes can cause the:

Answer 47

brakes to fade or fail

Question 48

How should you check that the spring brakes come on when air pressure in the system drops below a certain level?

Answer 48

Park on level ground, chock the wheels, release the parking brake whe you have enough pressure, shut the engine off, and repeatedly press and release the brake pedal

Question 49

The applicatipn pressure gauge shows how much air pressure you:

Answer 49

Are applying to the brakes

Question 50

What is emergency stab braking?

Answer 50

brake hard, release the brakes when the wheels lock, and reapply the brakes when the wheels start rolling

Question 51

Under normal conditions, to engage the parking brake the driver must first:

Answer 51

Let the air out of the spring brakes

Question 52

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

Answer 52

Either the front or rear brakes will not be fully operational

Question 53

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

Answer 53

Spring Pressure

Question 54

The air supply pressure gauge shows how much pressure:

Answer 54

Is in the air tanks

Question 55

All air brake equipped vehicles have:

Answer 55

An air supply pressure gauge

Question 56

If air pressure does NOT build up fast enough within the correct amount of time:

Answer 56

Your air pressure may drop too low during driving

Question 57

The spring brakes used on tractors and straight trucks will bring you truck to a stop when air pressure drops below ___ psi

Answer 57

20 psi

Question 58

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

Answer 58

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

Question 59

To check the brake slack on S-cam brakes, you should park on:

Answer 59

level ground, chock the wheels, and release parking brakes

Question 60

The air brake system for a straight truck or bus should not leak at a rate of more than ___ psi per minute with the engine OFF and the brakes released.

Answer 60

2 psi/min

Question 61

The air loss rate for a straight truck or bus wih the engine off and the brakes on should NOT be more than:

Answer 61

3 psi in one minute

Question 62

The safety valve is set to automatically reduce pressure at ___ psi

Answer 62

150 psi

Question 63

With air brake vehicles, the parking brakes should be used:

Answer 63

Whenever you leave the vehicle unattended

Question 64

A truck with air brakes going 55 mph would require a stopping distance of:

Answer 64

More than 300 feet

Question 65

If you vehicle has an alcohol eveporator, it is there to:

Answer 65

Reduce the risk of ice in air brake valves in cold weather

Question 66

The brake system that applies and releases the brakes when the driver uses the brake pedal is the ___ brake system.

Answer 66

Service

Question 67

The air compressor governor controls:

Answer 67

When air is pumped into the air tanks