Air brakes

Question 1

When is it ok to leave your truck unattended without applying the parking brakes and choking the wheels?

Answer 1

Never

Question 2

the stop light switch

Answer 2

turn on your brake lights to warn drivers behind you

Question 3

is not safe to drive a vehicle that has brake drums with cracks that are longer than BLANK of the width of the friction area

Answer 3

1/2

Question 4

to test air service brakes you should:

Answer 4

brake firmly while slowly moving forward

Question 5

a slack adjusters free play needs to be adjusted if it is more than about BLANK how many inches when you pull hard on it

Answer 5

1 INCH

Question 6

if air pressure is not built up within the correct amount of time, then

Answer 6

you air pressure may drop to a low point while driving, requiring an emergency stop

Question 7

the saftey valve reduces pressure at BLANK psi

Answer 7

150 PSI

Question 8

why should you drain the water from compressed air tanks?

Answer 8

water can freeze in cold weather and cause brake failure

Question 9

if your vehicle has an alcohol evaporator, every day cold weather you should

Answer 9

check and fill the alcohol level

Question 10

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

Answer 10

3 psi in 1 minute

Question 11

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

Answer 11

60 psi

Question 12

the air brake lag distance at 55 mph on dry pavement adds about BLANK feet

Answer 12

32 feet

Question 13

if your truck has a properly functioning dual air brake system and minimum size air tanks that air pressure should build up from 85 to 100 psi within how many seconds

Answer 13

45 seconds

Question 14

how should you check that your service brakes are working properly

Answer 14

park on a level ground, wait until normal air pressure is reached, release the parking brake and move forward slowly at 5 mph, than apply the brakes firmly using the brake pedal

Question 15

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

Answer 15

2 psi

Question 16

excessive use of the service brakes result in over heating which can lead to

Answer 16

expansion of the brake drums

Question 17

the safety valve is set automatically when pressure is

Answer 17

150 psi

Question 18

you truck and bus has a dual air brake system. if a low air pressure warning comes on for only one system, what should you do

Answer 18

stop right away and safely park. continue only after the system is fixed

Question 19

to check the free play of manual slack adjusters of s-cam brakes, you should park on

Answer 19

level ground, chock the wheels and release the parking brakes

Question 19

if you must make an emergency stop, you should brake so you

Answer 19

can steer and so you vehicle stays in a straight line

Question 19

the brake pedal in an air brake system

Answer 19

control the air pressure applied to put on the brakes

Question 19

all air brakes equipped vehicles have

Answer 19

a supply pressure gauge

Question 19

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

Answer 19

2 psi

Question 19

with air brake vehicles, the parking brakes should be used

Answer 19

whenever you leave the vehicle unattended

Question 20

the use of brakes on a long and steep downgrade under normal conditions is only a supplement to

Answer 20

the braking effect of the engine

Question 21

the most important thing to do when a low pressure warning comes on is

Answer 21

stop and safely park as soon as possible

Question 22

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

Answer 22

spring pressure

Question 23

why drain water from compressed air tanks

Answer 23

water can freeze in cold weather and cause failure

Question 24

repeatedly partially releasing and pressing the brake pedal may result in

Answer 24

a loss of brake air pressure

Question 25

the brake pressure system that applied and releases the brakes when the driver uses the brake pedal is the *BLANK* brake system

Answer 25

service

Question 26

a slack adjusters free play needs to be adjusted if it is more than about *BLANK* how many inches when you pull hard on it?

Answer 26

1 inch

Question 27

an air brake system is fully charged at what PSI

Answer 27

125 psi

Question 28

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

Answer 28

Never

Question 29

when the brakes are applied the brakes shoes will press against

Answer 29

brake drum or disc

Question 30

the safety valve discharges automatically at the pressure of

Answer 30

150 psi

Question 31

emergency stab braking is

Answer 31

press on the brake pedal as hard as you can, release the brakes when the wheels locked, put on the brakes again when the wheels start rolling

Question 32

why should you drain water from compressed air tanks

Answer 32

water can freeze in cold weather and cause brake failure

Question 33

modern air brakes systems combine 3 different systems. they are

Answer 33

Service parking emergency

Question 34

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

Answer 34

at the end of each day of driving

Question 35

the proper use of the brakes when going down a long steep grade after selecting a proper gear is to brake until your speed is about *BLANK* mph below the posted speed for your safety and release your brake

Answer 35

5 mph

Question 36

in ideal conditions a truck or bus with an air brake going 55 mph would require stopping of how many feet

Answer 36

more than 300 feet

Question 37

the application pressure gauge show how much air pressure you

Answer 37

are applying to the brakes

Question 38

the spring brakes used on the chambers in a straight truck will bring you to a stop when the air pressure drops below *BLANK* psi

Answer 38

20 psi

Question 39

some air brake systems had an alcohol evaporator. what may happen if you dont keep the proper level of alcohol?

Answer 39

ice may form in the air storage tank and cause brake failure

Question 40

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

Answer 40

bring your vehicle to a complete stop right away and safely park. continue only after the system is fixed

Question 41

when brakes are applied the brake shoes will align to press against the

Answer 41

brake drums or disc

Question 42

the braking power of spring brakes

Answer 42

depends on the service brakes being in adjustment

Question 43

the driver must be able to see a low air pressure warning which comes on before pressure in the service air tanks falls blow *BLANK* psi

Answer 43

60 psi

Question 44

which of these is not proper time to apply the parking brakes

Answer 44

to brake vehicle very hard, in other words when coming down a steep grade

Question 45

if you truck or bus has dual parking control valves, you can use pressure from separate tanks to

Answer 45

release the spring emergency/parking brake to move a short distance

Question 46

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

Answer 46

S-cam drums

Question 47

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

Answer 47

bring your vehicle to a safe stop and safely park, continue only after the system is fixed

Question 48

with air brake vehicle, the parking brakes should be used

Answer 48

anytime whe the vehicle is parked

Question 49

excessive heat caused by using the brakes too often can also cause

Answer 49

brake to fade or fail

Question 50

if you must make an emergency stop, you should brake so you

Answer 50

can steer and so your vehicle stays in a straight line

Question 51

the supply pressure gauge shows how much pressure

Answer 51

is in the air tanks

Question 52

if you are driving down a steeo downgrade and you have reached a speed of about 40 mph, you would apply the service brakes until you speed dropped to below *BLANK* mph

Answer 52

35 mph

Question 53

your truck has dual air brake system and one of the system loses pressure. what will happen

Answer 53

either the front or back brake will not be fully operational

Question 54

parking or emergency brakes of trucks and buses can be legally held on by *BLANK* pressure

Answer 54

spring pressure

Question 55

the S-cam

Answer 55

forces the brake shoes against the inside of the brake drum

Question 56

under normal conditions in order to engage the parking brake driver :

Answer 56

let the air out of the air brake system

Question 57

total stopped distance for air brakes is longer than hydraulic brakes due to *BLANK* distance

Answer 57

brake lag

Question 58

is it accepted that too much heat caused by using your brakes too often can also cause

Answer 58

brakes to fade or fail

Question 59

during normal driving, spring brakes are usually held back by

Answer 59

air pressure

Question 60

the air compressor stops pumping air at what PSI

Answer 60

125

Question 61

the supply pressure gauge show how much pressure

Answer 61

is in the air tanks

Question 62

the braking power or the spring brakes

Answer 62

depends on the service brakes being in adjustment

Question 63

why should you drain water from compressed air tanks

Answer 63

water can freeze in cold weather and cause brake failure

Question 64

if you must make an emergency stop, you should brake so you

Answer 64

can steer and so you vehicle stays in a straight line

Question 65

your brake are fading when

Answer 65

you have to push harder on the brake pedal to control your speed on downgrade

Question 66

if your vehicle has an alcohol evaporator, it is there to

Answer 66

reduce the risk of icing in air brake valves in cold weather

Question 67

the air compressor governor controls

Answer 67

when air is pumped into the air tanks

Question 68

air braking takes more time than hydraulic braking becuase air

Answer 68

takes more time to flow through the lines than hydraulic fluid