System_Components_and_Function

Question 1

What is the air brake system?

Answer 1

Brake system that uses compressed air to operate brakes

Question 2

What are the three air brake systems?

Answer 2

Service brakes, parking brakes, and emergency brakes

Question 3

What does the air compressor do?

Answer 3

Pumps air into air storage tanks

Question 4

What powers the air compressor?

Answer 4

Vehicle’s engine through belt or gear drive

Question 5

What controls the air compressor?

Answer 5

Governor that turns compressor on and off

Question 6

What is cut-in pressure?

Answer 6

Pressure at which air compressor starts pumping (around 100 psi)

Question 7

What is cut-out pressure?

Answer 7

Pressure at which air compressor stops pumping (around 125 psi)

Question 8

What does the safety valve do?

Answer 8

Prevents over-pressurization by releasing air at 150 psi

Question 9

What is the purpose of air storage tanks?

Answer 9

Store compressed air for brake system operation

Question 10

How many air tanks do most vehicles have?

Answer 10

At least two tanks for dual air brake systems

Question 11

What is the air dryer?

Answer 11

Removes moisture and oil from compressed air

Question 12

Why is the air dryer important?

Answer 12

Prevents ice formation and system contamination

Question 13

What are brake chambers?

Answer 13

Convert air pressure into mechanical force to apply brakes

Question 14

What is inside a brake chamber?

Answer 14

Diaphragm, return spring, and push rod

Question 15

What does the slack adjuster do?

Answer 15

Adjusts brake when air chamber pushes the push rod

Question 16

What are brake drums and linings?

Answer 16

Friction surfaces that create stopping power

Question 17

What does the treadle valve do?

Answer 17

Controls air flow to service brakes when you press brake pedal

Question 18

What is the parking brake control valve?

Answer 18

Yellow diamond knob that controls parking brakes

Question 19

What is the trailer brake hand valve?

Answer 19

Round blue knob for independent control of trailer brakes

Question 20

When should you use the trailer hand valve?

Answer 20

Only to test trailer brakes, never while driving

Question 21

What happens when you press the brake pedal?

Answer 21

Air flows from tanks to brake chambers to apply brakes

Question 22

What is service brake lag?

Answer 22

Time delay between pressing pedal and brakes actually working

Question 23

How long is normal brake lag?

Answer 23

About 0.5 seconds for air to flow and brakes to engage

Question 24

What are spring brakes?

Answer 24

Emergency/parking brakes that use spring power when air pressure is lost

Question 25

When do spring brakes automatically apply?

Answer 25

When air pressure drops to 20-40 psi range

Question 26

How do you release spring brakes?

Answer 26

Build air pressure above 60 psi and push in parking brake knob

Question 27

What should you never do with spring brakes?

Answer 27

Never push brake pedal when spring brakes are applied

Question 28

What is a modulating control valve?

Answer 28

Applies spring brakes gradually instead of full force

Question 29

What activates the stop light switch?

Answer 29

Pressing the service brake pedal

Question 30

What maintains air pressure in the system?

Answer 30

Air compressor controlled by governor

Question 31

What removes moisture from air tanks?

Answer 31

Manually draining tanks or automatic drain valves

Question 32

How often should you drain air tanks?

Answer 32

Daily or as recommended by manufacturer

Question 33

Why do you need to drain air tanks?

Answer 33

Remove moisture and oil that can damage system

Question 34

What happens if you don't drain tanks regularly?

Answer 34

Ice can form and block air lines in cold weather

Question 35

What pressure should air system maintain?

Answer 35

Between 100-125 psi during normal operation

Question 36

What indicates air compressor problems?

Answer 36

Low pressure, excessive cycling, or unusual noises

Question 37

How do you check air compressor belt?

Answer 37

Look for proper tension, cracks, or fraying

Question 38

What should air storage tanks be protected from?

Answer 38

Moisture, dirt, and damage from road debris

Question 39

What is an air pressure gauge?

Answer 39

Shows air pressure in brake system tanks

Question 40

How many air pressure gauges should dual systems have?

Answer 40

Two gauges or one gauge with two needles

Question 41

What does alcohol do in air brake systems?

Answer 41

Helps prevent ice formation in air lines

Question 42

When might alcohol be added to air systems?

Answer 42

In cold weather to prevent freezing

Question 43

What maintains proper brake adjustment?

Answer 43

Automatic slack adjusters or manual adjustment

Question 44

How often should brake adjustment be checked?

Answer 44

During daily pre-trip inspection

Question 45

What indicates brake system problems?

Answer 45

Low air pressure, warning lights, or poor brake performance

Question 46

What is the foundation brake?

Answer 46

Brake components at each wheel (drums, shoes, chambers)

Question 47

How do foundation brakes work?

Answer 47

Air pressure pushes brake shoes against drums to create friction

Question 48

What connects air tanks to brake chambers?

Answer 48

Air lines and control valves

Question 49

What regulates air flow to different brake circuits?

Answer 49

Various control valves throughout the system

Question 50

What is the most critical air brake system component?

Answer 50

Air compressor because it provides power for entire system