Air Brakes Cdl Exam Questions

Front 1

The application pressure gauge shows how much air pressure you

Back 1

Are applying to the brakes

Front 2

The spring breaks used on the chamber in a straight truck will bring you to a stop one air pressure drops below ___ PSI

Back 2

20

Front 3

Some air brake systems have an alcohol evaporator what may happen if you don't keep the proper level of an alcohol

Back 3

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

Front 4

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

Back 4

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

Front 5

Why drain water from compressed air tanks

Back 5

Water can freezing cold weather in cause brake failure

Front 6

The safety valve a set automatically when pressure is

Back 6

150 your truck has a dual air system and one of the systems loses its pressure. What will happen

Front 7

Your truck has a dual air system and one of the systems loses its pressure. What will happen

Back 7

Either the front or back break will not be fully operational

Front 8

Parking or emergency brakes of trucks and buses can be legally held on by______pressure

Back 8

Spring

Front 9

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

Back 9

Release this bring emergency parking brakes to move a short distance

Front 10

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

Back 10

45

Front 11

How should you check that your service brakes are working properly

Back 11

Park on level ground. Wait until normal air pressure is reached release a parking brake and move forward slowly at about 5 mph. Then apply the brakes firmly using the break

Front 12

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

Back 12

2

Front 13

During normal driving spring breaks are usually held back by

Back 13

Air pressure

Front 14

The air compressor stops pumping air at what PSI

Back 14

125

Front 15

The driver must be able to see a low air pressure warning which comes on before pressure in the service air tanks fall below____ PSI

Back 15

60

Front 16

Excessive use of the service breaks result in overheating which can lead to

Back 16

Expansion of the brake drums

Front 17

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

Back 17

S – cam drum

Front 18

If you must make an emergency stop you should break so you

Back 18

Can steer and so your vehicle stays in a straight line

Front 19

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

Back 19

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

Front 20

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

Back 20

Check and fill the alcohol level

Front 21

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

Back 21

Three PSI in one minute

Front 22

The driver must be able to see a low pressure warning which comes on for pressure in the service air tanks fall below____psi

Back 22

60

Front 23

The breaking power of the spring breaks

Back 23

Depends on the service breaks being in adjustment

Front 24

The airbrake lag distance at 55 mph on dry pavement adds about_____feet

Back 24

32 feet

Front 25

Total stopping distance for airbrakes is longer than that for hydraulic breaks due to ____distance

Back 25

Breaking lag

Front 26

It is excepted that too much heat caused by using your brakes too often could also cause

Back 26

Break to fade or fail

Front 27

Repeatedly partially releasing impressing the brake pedal may result in

Back 27

A loss of break air pressure

Front 28

The brake system that applies and releases the Brakes when the driver uses the brake pedal is the________ break system

Back 28

Service

Front 29

A slacking adjusters free play needs to be adjusted if it's more than about_____.. how many inches when you pull hard on it

Back 29

1inch

Front 30

And air brake system is fully charged at what PSI

Back 30

125

Front 31

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

Back 31

Bring the vehicle to a safe stop and safely Park continue only after the system is fixed

Front 32

The brake pedal and an air brake system

Back 32

Controls the air pressure applied to put on the brakes

Front 33

The S-cam

Back 33

Forces the brake shoes against the inside of the brake drum

Front 34

Under normal conditions in order to engage the parking brake driver

Back 34

Let the air out of the air brake system

Front 35

All airbrake equipped vehicles have

Back 35

A supply pressure gauge

Front 36

With airbrake vehicles the parking brake should be used

Back 36

Whenever you leave the vehicle unattended

Front 37

A straight truck or bus airbrake system should not leak at the rate of more than ____PSI per minute with the engine off and the brakes released

Back 37

2

Front 38

Which of these is not a proper time to apply the parking brake

Back 38

To break the vehicle very hard and other word when coming down the steep grade

Front 39

With airbrakes vehicles the parking brake should be used

Back 39

Anytime when the vehicle is parked

Front 40

Why should you drain the water from the compressed air tanks

Back 40

Water can freezing cold weather and cause brake failure

Front 41

If the spring breaks are on when should you push the brake pedal

Back 41

Never

Front 42

To check the free play of manual slack adjusters of s-cam breaks you should park on

Back 42

Level ground check the wheels and release the parking break

Front 43

Excessive heat caused by using your brakes too often could also cause

Back 43

Breaks to fade or fail

Front 44

The use of brakes on a long and Steep Downgrade under normal conditions it's only a supplement to

Back 44

The breaking effect of the engine

Front 45

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

Back 45

Stop and safely parked as soon as possible

Front 46

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

Back 46

Sring pressure

Front 47

Air breaking takes more time than hydraulic breaking because air

Back 47

Takes more time to flow through the lines than hydraulic fluid

Front 48

When brakes are applied the brakes shoes will Press against the

Back 48

Brake drum or disc

Front 49

The safety valve discharges automatically at pressure of

Back 49

150

Front 50

Emergency stap breaking is

Back 50

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

Front 51

If the air pressure is not built up with in the correct amount of time then

Back 51

Your air pressure may drop to a low point while driving requiring emergency stop

Front 52

Safety valve reduce pressure at ______PSI

Back 52

150

Front 53

The supply pressure gauge shows how much pressure

Back 53

Is in the air tanks

Front 54

The breaking power of the spring breaks

Back 54

Depends on the service breaks being in adjustment

Front 55

Your brakes are fading when

Back 55

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

Front 56

The air compressor governor controls

Back 56

When air is pumped into the air tanks

Front 57

Modern air brake systems combine three different systems they are The service,

The parking and the_____ brakes

Back 57

Emergency

Front 58

If you do not have automatic tank drains how often should you drain the oil and water for the bottom of the compressed air storage tanks

Back 58

At the end of each day of driving

Front 59

The proper use of the brakes when going down the long steep grade after selecting a proper gear is to break until your speed is about_______\ miles per hour below the posted speed for your safety and release your breaks

Back 59

5 mph

Front 60

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

Back 60

More than 300 feet

Front 61

When is it OK to leave your truck unattended without applying the parking brakes and choking the wheel

Back 61

Never

Front 62

The stop light switch

Back 62

Turns on your brake lights to Warn drivers behind you

Front 63

It is not safe to drive a vehicle that has brake drums with cracks in there longer than_____ of the width of the friction area

Back 63

1/2

Front 64

To test air service breaks you should

Back 64

Break firmly while slowly moving forward

Front 65

If you're driving down to the steep downgrade and you have rates of speed of 40 Miles per hour. You would apply the service break until your speed drop to below____ miles per hour

Back 65

35

Front 66

To check slack adjusters on S Cam brakes

Back 66

Park on level ground and chock the wheels to prevent the vehicle from moving release the parking break so you can move the slack adjusters