Air Brakes

Question 1

When is it OK to leave your truck unattended without applying the parking brakes and choking wheels?
a) never
b) if you are only away for a few minutes
c) if you are conducting a pre-trip inspection

Answer 1

a) never

Question 2

The stop light switch?
a. tells you when the air brake system has low air pressure
b. tells you when. you need to use your emergency brakes
c. turns on your brake lights to warn drivers behind you

Answer 2

c. turns on your brake lights to warn drivers behind you

Question 3

It is not safe to drive a vehicle that has brake drums with cracks that are no longer than ____________ of the width of the friction area
a. 1/2
b. 1/4
c. 1/8

Answer 3

a. 1/2

Question 4

To test air service brakes, you should:
a. stop the vehicle, brake in a low gear, depress the service brakes, and then gently pull against the brakes
b. brake firmly while slowly moving forward
c. brakes slowly moving backwards

Answer 4

b. brake firmly while slowly moving forward

Question 5

A slacker adjuster’s fee play needs to be adjusted if it is more than about _________ how many inches when you pull hard on it?
a. 1/4in
b. 1/2in
c. 1in

Answer 5

c. 1in

Question 6

If air pressure is not built up within the correct amount of time, then:
a. you should be ready to use your parking brakes to stop
b. the alcohol container may be low
c. your air pressure may drop to a low point while driving, requiring an emergency stop

Answer 6

c. your air pressure may drop to a low point while driving, requiring an emergency stop

Question 7

The saftey valve reduces pressure at _________ psi?
a. 50
b. 100
c. 150

Answer 7

c. 150

Question 8

Why should you drain water from compressed air tanks?
a. waters low boiling point reduces braking powder
b. water can freeze in cold weather and cause brake failure
c. water cools the compressor too much

Answer 8

b. water can freeze in cold weather and cause brake failure

Question 9

If your vehicle has an alcohol evaporator, every day during cold weather you should?
a. check and fill the alcohol level
b. change the alcohol from a new bottle
c. check the oil for alcohol content

Answer 9

a. check and fill the alcohol level

Question 10

The air loss rate for straight truck or bus with the engine off and the brakes on should not be more than:
a. 1 psi in 30 secs
b. 2psi in 45 secs
c. 3 psi in 1min

Answer 10

c. 3 psi in 1min

Question 11

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
a. 50
b. 60
c. 80

Answer 11

b. 60

Question 12

The air brake lag in distance at 55mph on dry pavement adds about _______ feet
a. 12
b. 32
c. 52

Answer 12

b. 32

Question 13

If your truck has a properly functioning dual air brake system minimum size air tanks, the air pressure should build up from 85 to 100 psi within how many secs?
a. 60
b. 30
c. 45

Answer 13

c. 45

Question 14

How should you check that your service brakes are working properly?
a. park on slight grade, drain off pressure, set parking brake and check to the movement
b. park on a level ground, chock the wheels, engage the parking brakes when you have the correct amount of air pressure to do so and shut the engine off
c. park on level ground, wait until normal air pressure is reached, release the parking brake and move forward slowly at about 5mph. Then apply the brakes firmly using the brake pedal

Answer 14

c. park on level ground, wait until normal air pressure is reached, release the parking brake and move forward slowly at about 5mph. Then 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 ____ psi per minute with the engine off and the brakes released
a. 1
b. 2
c. 3

Answer 15

c. 3

Question 16

Excessive use of the service brakes results in overheating which can lead to:
a. proper adjustment of S-cam
b. increase contact between the brake drums and linings
c. expansion of the brake drums

Answer 16

c. expansion of the brake drums

Question 17

The safety valve is set automatically when pressure is:
a. 50
b. 100
c. 150

Answer 17

c. 150

Question 18

If you must make an emergency stop, you should brake so you:
a. use the handbrake before the brake pedal
b. can steer and so your vehicle stays in a straight line
c. use the full power of the brakes to lock them

Answer 18

b. can steer and so your vehicle stays in a straight line

Question 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?
a. reduce your speed and drive to the nearest garage for repairs
b. reduce your speed and test the remaining system while under way
c. stop right away and safety park. continue only after the system is fixed

Answer 19

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

Question 20

The brake pedal in an air brake system:
a. controls the speed of the air compressor
b. controls the air pressure applied to put on the brakes
c. is connected to slack adjusters by a series of rods and linages

Answer 20

b. controls the air pressure applied to put on the brakes

Question 21

All air brakes equipped vehicles have:
a. a supply pressure gauge
b. an air usage gauge
c. a backup hydraulic system

Answer 21

a. a supply pressure gauge

Question 22

With air brake vehicles, the parking brakes should be used:
a. whenever you leave the vehicles unattended
b. as little as possible
c. only during pre and post-trip inspections

Answer 22

a. whenever you leave the vehicles unattended

Question 23

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
a. 1
b. 2
c. 3

Answer 23

c. 3

Question 24

To check the free play of manual slack adjuster of S-cam brakes, you should park on:
a. level ground, chock wheels and release the parking brakes
b. level ground and apply the parking brakes, then apply service brakes
c. level ground and drain off air pressure before checking the adjustment

Answer 24

a. level ground, chock wheels and release the parking brakes

Question 25

The use of brakes on a long steep downgrade under normal conditions is only a supplement to: a. use of spring brakes b. the use of the front brakes limiting valve c. the braking effect of the engine

Answer 25

c. the braking effect of the engine

Question 26

The most important thing to do when a low air pressure warning comes on is: a. upshift b. downshift c. stop and safely brake as soon as possible

Answer 26

c. stop and safely brake as soon as possible

Question 27

The parking or emergency brake on heavy vehicle can only be held in position by something that cannot leak away, like: a. spring pressure b. air pressure c. hydraulic pressure

Answer 27

a. spring pressure

Question 28

Repeatedly partially releasing and pressing the brake pedal may result in: a. a loss of brake air pressure b. a buildup of brake air pressure c. no change of brake air pressure

Answer 28

a. a loss of brake air pressure

Question 29

The brake system that applies and releases the brakes when the driver uses the brake pedal is the _______ brake system a. emergency b. service c. parking

Answer 29

b. service

Question 30

A slack adjuster's free play needs to be adjusted if it is more than about ______ when you pull hard on it? a. 1/4 in b. 1/2 in c. 1 in

Answer 30

c. 1 in

Question 31

An air brake system is fully charged at what psi? a. 75 b. 100 c. 125

Answer 31

c. 125

Question 32

If the spring brakes are on, when should you push the brake pedal? a. only when driving downhill b. only a the slippery road c. never

Answer 32

c. never

Question 33

When brakes are applied the brake shoes will press against the: a. brake drum or disk b. slack adjuster c. S-cam

Answer 33

a. brake drum or disk

Question 34

The safety valve discharges automatically at the pressure of: a. 50 b. 100 c. 150

Answer 34

c. 150

Question 35

Emergency stab braking is: a. when you press hard on a brake pedal and apply hand valve while you stop b. use light steady pressure on the brake pedal c. press on the brake pedal as hard as you can, release the brakes when the wheels locked, brakes again when the wheels start rolling

Answer 35

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

Question 36

Why should you drain water from compressed air tanks? a. water low boiling point reduces braking power b. water can freeze in cold weather and cause brake failure c. to keep from fouling the air compressor oil

Answer 36

b. water can freeze in cold weather and cause brake failure

Question 37

Modern air brakes systems combine three different systems. They are the service, the parking, and the _______ brakes a. emergency b. foot c. drum

Answer 37

a. emergency

Question 38

If you do not have automatic tank drains, how often should you drain compressed air storage tanks? a. after every four hours of service b. at the end of each day driving c. once a week

Answer 38

b. at the end of each day driving

Question 39

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 ______ mph below the posted speed for your safety and release your brake a. 5mph b. 15mph c.10mph

Answer 39

a. 5mph

Question 40

In ideal conditions a truck or bus with an air brake going at 55 mph would required stopping distance of how many feet? a. less than 100 ft b. more than 300 ft c. from 100 to 300 ft

Answer 40

b. more than 300 ft

Question 41

The application pressure gauge shows how much air pressure you: a. have in the air tanks b. are applying to the brakes c. have in a modulating control valve

Answer 41

b. are applying to the brakes

Question 42

The spring breaks used on the chamber in a straight truck will bring you to a stop when air pressure drops below _______ psi a. 20 b.60 c. 100

Answer 42

a. 20

Question 43

Some air brake systems have an alcohol evaporator. what may happen if you don't keep the proper level of alcohol? a. the S-cam may not take back when you release the brake pedal b. ice may form in the air storage tank and cause brake failure c. ice may form on the brake drums and wear them out

Answer 43

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

Question 44

Your truck or bus has a dual air brake system. If a low air pressure warning comes on for only one, what should you do? a. bring your vehicle to a complete stop right away and safety park. Continue only after the system is fixed b. reduce your speed, and test the remaining system while under way c. reduce your speed and drive to the nearest garage for repairs

Answer 44

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

Question 45

When brakes are applied the brake shoes will align to press against the: a. brake drum or disk b. slack adjuster c. S-cam

Answer 45

a. brake drum or disk

Question 46

The braking power of the spring brakes: a. is not affected by the condition of the service brakes b. depends on the service brakes being in adjustment c. increases when the service brakes are hot

Answer 46

b. depends on the service brakes being in adjustment

Question 47

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 a. 40 b. 60 c. 80

Answer 47

b. 60

Question 48

Which of the following of these is NOT a proper time to apply the parking brakes? a. if the brakes are very hot (eg after just coming down a steep grade) b. to use parking brakes if you park for less than 10 mins c. if you are going to use the parking brakes, you need to make sure they will hold the vehicle

Answer 48

a. if the brakes are very hot (eg after just coming down a steep grade)

Question 49

If your truck or bus has dual parking control valves, you can use pressure from a separate tank to: a. balance the service brake system when you are parked b. stay parked twice as long without using up service air pressure c.release the spring emergency/ parking brakes to move a short distance

Answer 49

c.release the spring emergency/ parking brakes to move a short distance

Question 50

The most common type of foundation rake found on heavy vehicles is the: a. wedge drum b. S-cam drum c. disk

Answer 50

b. S-cam drum

Question 51

If your truck or bus has a dual air brake system. if a low air pressure warning comes on for only one, what should you do? a. bring the vehicle to a safe stop and safety park. Continue only after the system is fixed b. reduce your speed the remaining system under way c. reduce your speed and drive to the nearest garage for repairs

Answer 51

a. bring the vehicle to a safe stop and safety park. Continue only after the system is fixed

Question 52

With air brake vehicles, the parking brakes should be used: a. as little as possible b. any time vehicle is parked c. to hold your speed when going downhill

Answer 52

b. any time vehicle is parked

Question 53

Excessive heat caused by using your brakes too often can also cause: a. modulated control valve to wear out b. brake linings to split up c. brake to fade or fail

Answer 53

c. brake to fade or fail

Question 54

If you must make an emergency stop, you should brake so you: a. can steer while braking hard b. can steed and so your vehicle stays in a straight line c. use the hand

Answer 54

b. can steed and so your vehicle stays in a straight line

Question 55

The supply pressure gauge shows how much pressure: a. is in the air tanks b. you have used in this trip c. is going to the brake chamber

Answer 55

a. is in the air tanks

Question 56

If you are driving down a steep downgrade and you have reached the speed of 40 mph, you would apply the service brake until your speed dropped to below _______ mph a. 25 b. 30 c. 35

Answer 56

c. 35

Question 57

Parking or emergency brakes of trucks and buses can legally be held on by ________ pressure a. spring b. air c. fluid

Answer 57

a. spring

Question 58

The S-cam: a. controls the flow air to each of the brakes chambers b. pulls the brake shoes away from the drum and allow the wheels to roll freely c. forces the brake shoes against the inside of the brake drums

Answer 58

c. forces the brake shoes against the inside of the brake drums

Question 59

Under normal conditions, in order to engage the parking brakes, driver must: a. turn off the engine b. let the air out of air brake system c. be sure air brakes system is fully pressurized

Answer 59

b. let the air out of air brake system

Question 60

Total stopping distance for air brakes is longer than that for hydraulic brakes due to ________ distance a. braking lag reaction effective braking

Answer 60

a. braking lag

Question 61

It is accepted that too much heat caused by using your brakes too often can also cause: a. modulated air valve to wear out b. brake lining to split up c. brake to fade or fail

Answer 61

c. brake to fade or fail

Question 62

During normal driving, spring brakes are usually held back by: a. bolds of clamp b. air pressure c. spring pressure

Answer 62

b. air pressure

Question 63

The air compressor stops air at what psi? a. 100 b. 125 c. 150

Answer 63

b. 125

Question 64

The supply pressure gauge shows how much pressure: a. is in the air tanks b. tractor brake lines c. trailer brake lines

Answer 64

a. is in the air tanks

Question 65

The braking power of the spring brakes: a. depends on the service brakes being in adjustment b. is not affected by the condition of the service brakes c. can only be tested by highly-trained brake service technicians

Answer 65

a. depends on the service brakes being in adjustment

Question 66

Your brakes are fading when: a. you have to push harder on a brake pedal to control your speed on a downgrade b. less pressure is needed on the brake pedal for each stop c. the brake pedal feels spongy when you apply pressure

Answer 66

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

Question 67

The air compressor governor controls: a. the speed of the vehicle b. the temperature of air pumped into the storage tanks c. how fast air is pumped into the air storage tanks

Answer 67

c. how fast air is pumped into the air storage tanks

Question 68

Air braking takes more time than hydraulic braking because air: a. air brakes use different brake drums b. takes more time to flow through the lines than hydraulic fluid c. brakes require heavier return springs

Answer 68

b. takes more time to flow through the lines than hydraulic fluid