Air Brakes

Front 1

Which of the following is okay to find I the air brake system?

Back 1

Air

Front 2

Air loss in a single vehicle (not a combination unit) should no be more than _______ with the engine off and the brakes on.

Back 2

3 psi in one minute

Front 3

The vehicle must have a warning device which comes on when the air pressure in the service air tanks falls below:

Back 3

60 psi

Front 4

If the air system should develop a leak, what will keep air in the tanks?

Back 4

The one-way check valve

Front 5

Which brake system applies and releases the brakes when the driver uses the brake pedal?

Back 5

The service brake system

Front 6

When using the parking brakes or emergency brakes, what type of pressure is being used?

Back 6

Spring pressure

Front 7

The air loss rate for a straight truck or bus with the engine off and the brakes applied should not be more than:

Back 7

3 psi in one minute

Front 8

Air brakes equipped vehicles must have:

Back 8

An air pressure gauge, to show the pressure available for braking

Front 9

Which of the following statements about brakes is true?

Back 9

The heavier a vehicle or the faster it is moving, the more heat the brakes have to absorb to stop it

Front 10

Three different systems are found on modern air brake systems; service brakes, parking brakes, and:

Back 10

Emergency brakes

Front 11

The purpose of engine retarders is to :

Back 11

Help slow the vehicle while driving and reduce brake wear

Front 12

If your vehicle is equipped with an alcohol evaporator, every day during winter you should:

Back 12

Check the alcohol level and fill if necessary

Front 13

The air supply pressure gauge shows the driver how much pressure:

Back 13

Is available in the air tanks

Front 14

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

Back 14

S-cam drum

Front 15

A straight truck or bus air brake system cannot leak more than how many psi per minute with the engine off and the brakes released?

Back 15

2 psi

Front 16

How do you check the free play in manual slack adjusters?

Back 16

Park on level ground, chock wheels, release the parking brakes and pull slack adjusters

Front 17

Which of the following answers is most correct about brake use on a long and steep downgrade?

Back 17

Use the braking effects of the engine, and when the vehicle speed reaches the "safe" speed, apply brakes firmly until the vehicle speed is reduced to approximately 5 mph below "safe" speed

Front 18

When a failure occurs in the service brake system, the system you need to use to stop the vehicle is the:

Back 18

Emergency brake system

Front 19

A combination vehicle air brakes system cannot leak more than how many psi per minute with the engine off and the brakes released?

Back 19

3 psi

Front 20

The brake pedal:

Back 20

Controls the air pressure applied to operate the brakes

Front 21

During normal operations, the parking and emergency brakes are usually held back by?

Back 21

Air pressure

Front 22

Why should you not fan the brakes on and off during long downgrades?

Back 22

The short time off the brakes does not allow for brake cooling

Front 23

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

Back 23

Emergency

Front 24

The driver must be able to see a warning before air pressure in the service air tanks falls below _____ psi.

Back 24

60

Front 25

The brake pedal in an air brake system:

Back 25

Controls the air pressure applied to the brakes

Front 26

Air brakes takes more time than hydraulic raking because air:

Back 26

Takes more time to flow through the lines than hydraulic fluid

Front 27

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

Back 27

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

Front 28

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

Back 28

Release the spring emergency parking brakes to move a short distance

Front 29

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

Back 29

Level ground, chock wherls, and turn off the parking brakes

Front 30

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

Back 30

Stop and safely park as soon as possible

Front 31

The air compressor governor controls?

Back 31

When air is pumped in to the tanks

Front 32

The braking power of the spring brakes:

Back 32

Depends on whether the service brakes are in adjustment

Front 33

All vehicles equipped with air brakes have:

Back 33

A supply pressure gauge

Front 34

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

Back 34

Can steer and your vehicle stays in a straight line

Front 35

If you do not have automatic tank drains, how often should you drain the oil and water fro. The bottom of compressed air storage tanks?

Back 35

At the end of each day of driving

Front 36

The application pressure gauge shows how much air pressure you:

Back 36

Are applying to the brakes

Front 37

Your brakes are fading when:

Back 37

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

Front 38

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

Back 38

Check the alcohol level and fill the evaporator if needed

Front 39

Why should you drain water from compressed air tanks

Back 39

Water can freeze jn cold weather and cause brake failure

Front 40

Your vehicle has a dual air brake system. If low air pressure warning comes on for the secondary system, you should:

Back 40

Bring the vehicle to a safe stop and continue only when the system is repaired

Front 41

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

Back 41

Air pressure

Front 42

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

Back 42

Anytime the vehicle is parked

Front 43

Emergency stab braking is when you:

Back 43

Brake as hard as you can, release the brake when the wheels lock, then push the brakes again when the wheels start rolling

Front 44

A straight truck brake system should not leak at a rate of more than _____ psi per minute with the engine off and the brakes released.

Back 44

2

Front 45

The air loss rate for a straight truck with the engine off and the brakes on should not be more than:

Back 45

3 psi in one minute

Front 46

The supply pressure gauge shows how much pressure:

Back 46

Is in the air tanks

Front 47

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

Back 47

Service

Front 48

Total stopping distance for air brakes is longer that that foe hydraulic brakes due to _____ distance.

Back 48

Brake lag

Front 49

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

Back 49

S-cam drum brake

Front 50

If the air compressor develops a leak, what keeps the air in the tank?

Back 50

The one-way check valve

Front 51

Air brakes take more time to activate than hydraulic brakes because:

Back 51

It takes air longer to flow through the lines

Front 52

Why is the stopping distance for air brakes longer that hydraulic drakes?

Back 52

Brake lag distance

Front 53

What does the air compressor governor control?

Back 53

The air pumped into the sir tanks

Front 54

You should drain water from compressed air tanks because:

Back 54

Water can freeze and cause brake failure

Front 55

In cold weather, what should you do to an alcohol evaporator?

Back 55

Check and fill the alcohol level

Front 56

In an air brake system, a brake pedal:

Back 56

Controls the air pressure applied to the brakes

Front 57

What do all air brake-equipped vehicles have?

Back 57

An air supply pressure gauge

Front 58

The air supply pressure gauge indicates:

Back 58

The pressure in the air tank

Front 59

The purpose of a dual parking control valves is :

Back 59

To release the spring brake Ina an emergency

Front 60

On an long downgrade, how can you tell if your brakes and fading?

Back 60

You have to push harder to control your speed

Front 61

How should the free play of manual slack adjusters on S-cam brakes be checked?

Back 61

Park on level ground, chock the wheels, turn off the parking brakes

Front 62

The air pressure warning light should come on before the pressure gets below:

Back 62

60 psi

Front 63

What are spring brakes held back by?

Back 63

Air pressure

Front 64

If there is a leak in the air brake system, the parking or emergency brake can be held in position only by:

Back 64

Spring pressure

Front 65

You have a problem if you are testing the service brakes and notice that:

Back 65

They have an unusual feel

The vehicle pulls to one side

Stopping action is delayed

Front 66

The dual air brake system operates on which axle (s)?

Back 66

The rear axle

The front axle

The trailer axle

All axles

Front 67

When checking to make sure the spring brakes come on automatically, the parking brake know should pop out when:

Back 67

The air pressure falls to between 20 and 40 psi

Front 68

During an emergency stop, how should you brake?

Back 68

Brake so you can steer and stay in a straight line

Front 69

During an emergency stop, how should you brake?

Back 69

Brake so you can steer and stay in a straight line

Front 70

Why is controlled stab braking better than short, light brake pedal pressure on long downhill grades?

Back 70

Light pressure heats up the brakes

Front 71

When a low air pressure warning comes on, you should:

Back 71

Stop and park as soon as possible

Front 72

When do you use the parking brake in air barke-equipped vehicle?

Back 72

Any time you park

Front 73

If it is not done automatically in your vehicle, how often should you drain your air tanks?

Back 73

At the end of each day of driving.

Front 74

What are the three braking systems?

Back 74

The service brake and the parking brake and the emergency system

Front 75

What is used to make the brakes work?

Back 75

Compressed air

Front 76

What does the air compressor do?

Back 76

Pumps air into the air storage tanks

Front 77

What does the air compressor Governor control?

Back 77

It controls when the compressor will pump air into the air storage tanks

Front 78

How much compressed air must the storage tanks hold?

Back 78

Enough air to allow breaks to be used when the air compressor stops working

Front 79

If oil and water collect in the air tanks what can happen to the brakes?

Back 79

The brakes can fail

Front 80

No automatic tank drains - when should you drain the air tank?

Back 80

Everyday

Front 81

Where will you find the drain valve for each air tank?

Back 81

In the bottom of the tank

Front 82

What are the two types of air tank drains?

Back 82

Manually operated... Automatic

Front 83

What is a purpose of an alcohol evaporator?

Back 83

It reduces risk of ice and Brake valves and other parts in cold weather

Front 84

How often should you check the alcohol evaporator in cold weather?

Back 84

Check the alcohol container and fill up as necessary every day

Front 85

What is a purpose of the safety release valve in the first tank?

Back 85

It protects the tank and the rest of the system from too much pressure

Front 86

What are two other names for the brake pedal?

Back 86

It can be called the foot valve or treadle valve

Front 87

What can happen if the brake pedal is pressed and released too often?

Back 87

Air can be let out of the system faster than the compressor can replace

Front 88

Where are Foundation brakes found?

Back 88

At each wheel

Front 89

Where are brake shoes and Linings located?

Back 89

Inside each brake drum

Front 90

What happens when a brake lining is pushed against the inside of the drum?

Back 90

This causes friction which slows the vehicle and creates Heat

Front 91

On s-cam brakes what happens to the air when you push the brake pedal?

Back 91

Air pressure forces out the push rod and moves the slack adjuster

Front 92

Which direction does the s - cam Force brake shoes when brakes are applied?

Back 92

It presses them against the inside of the brake drum

Front 93

If the air compressor begins to leak what keeps air in the tanks?

Back 93

The one - way check valve

Front 94

What is one kind of gauge that is required for vehicles with air brakes?

Back 94

An air pressure gauge

Front 95

What kind of warning signal is required on vehicles with air brakes?

Back 95

A low air pressure warning signal

Front 96

What are the three types of low air pressure warning devices?

Back 96

A red light... Or a buzzer... Or a wig wag

Front 97

What is used to turn on the stop lights in an air brake system?

Back 97

An electric switch that works by air pressure

Front 98

In normal driving parking and emergency brakes are usually held back by?

Back 98

Air pressure

Front 99

The effectiveness of the spring brakes are usually held back by?

Back 99

Service brakes

Front 100

Why do some buses have a separate air tank to release spring brakes?

Back 100

So you can move the vehicle in an emergency

Front 101

What is a dual air brake system?

Back 101

Two separate air brake systems with a single set of brake controls

Front 102

What should you look for in checking an air compressor belt?

Back 102

Check belts for excessive wear and cracks and tightness

Front 103

What should you do before checking free play in manual slack adjusters?

Back 103

Park on level ground and choke the wheels and release parking brakes

Front 104

Combination vehicles: brakes released. The maximum air released?

Back 104

Less Than 3 pounds per square inch

Front 105

Single vehicle: brakes released. Maximum air leakage in one minute?

Back 105

Less than 2 pounds per square inch

Front 106

After applying brakes fully, maximum air loss in one minute - single vehicles?

Back 106

3 pounds per square inch

Front 107

After applying brakes fully Max. Hair loss in one minute - combination vehicle?

Back 107

4 pounds per square inch

Front 108

When should the air governor cut out the air compressor?

Back 108

At about the manufacturer specified air pressure

Front 109

When making a normal stop when should you push in the clutch?

Back 109

Do not push the clutch in until the engine RPMs are down close to idle

Front 110

When making a very quick stop you should break so that you?

Back 110

Stay in a straight line and can steer

Front 111

What is another name for controlled braking?

Back 111

Squeeze braking

Front 112

What is stab braking?

Back 112

Pressing the brake pedal and releasing brakes when Wheels lock up

Front 113

Why does air braking take more time than hydraulic braking?

Back 113

Because it takes time for air to flow through the lines to the brakes