Air Brakes

Front 1

The use of air brakes on a downgrade is only a supplement to the

A. use of the spring brakes

B. use of the front brake limiting valve

C. braking effect of the engine

Back 1

C. Braking effect of the engine

Front 2

The air brake lag distance at 55 mph on dry pavement adds about ____ feet to your stopping distance

A. 12

B. 52

C. 32

Back 2

C. 32

Front 3

All air brake equipped vehicles have

A. an air supply pressure gauge

B. an air use gauge

C. a backup hydraulic system

Back 3

A. An air supply pressure gauge

Front 4

The brake 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.

Back 4

B. Depends on the service brakes being in adjustment

Front 5

If your trucks air compressor has its own oil supply Chen should you first check the oil level ?

A. before driving

B. during your first en route inspection

C. immediately after you stop driving

Back 5

A. Before driving

Front 6

If your vehicle has an alcohol evaporator it is there too...

A. rid the wet tank of alcohol that condenses and sits at the bottom

B. eliminate the need for daily tank draining

C. reduce the risk of ice in air brake valves in cold weather.

Back 6

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

Front 7

During normal driving g spring brakes are usually held back by ?

A. bolts

B. spring pressure

C. air pressure.

Back 7

C. Air pressure

Front 8

What is emergency Stab braking?

A. press hard on the brake pedal and apply full hand valve utile you stop.

B. use light steady pressure on the brake pedal

C. brakes when the wheels start rolling

Back 8

C. Brakes when the wheels start rolling

Front 9

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

A. upshift and drive to a safe place

B. downshift and drive to a safe place

C. stop and safely park as soon as possible.

Back 9

C. Stop and safely park as soon as possible

Front 10

If you must make an emergency stop brake so you

A. can steer hard while braking hard

B. use the hand brake first

C. can steer your vehicle in a straight line

Back 10

C. Can steer your vehicle in a straight line

Front 11

a truck with air brakes going 55 mph would require a stopping distance of

A. less than 100 feet

B. 100-300 feet

C. mare than 300 feet

Back 11

C. more than 300 feet

Front 12

the air compressor should stop pumping at about

A. 100 psi

B. 125 psi

C. 150 psi

Back 12

B. 125 psi

Front 13

your vehicle has a dual air brake system if a low air pressure warning comes on for the secondary system you should

A. stop the vehicle and continue only when the system is fixed

B. reduce your speed and test the remaining system while driving

C. reduce your speed and drive to the nearest garage for repairs.

Back 13

A. stop the vehicle and continue only when the system is fixed.

Front 14

the safety valve is usually set to reduce air pressure at____ psi

A. 50

B. 125

C. 150

Back 14

B. 125

Front 15

your truck has a property functioning dual air brake system and minimum size air tanks. the air pressure should build from 85 to 100 psi within

A. 30 seconds

B. 45 seconds

C. 60 seconds

Back 15

B. 45 seconds

Front 16

how should you check that your service brakes are working properly?

A. park on a slight incline drain off air pressure set the parking brakes

B. park on a level ground check the wheel engage the parking brake and shut the engine off

C. wait for normal air pressure,, release the parking brake, move the truck forward slowly, and firmly step on the brake

Back 16

C. wait for normal air pressure release the parking brake move the truck forward slowly and firmly step on the brake

Front 17

repeatedly pressing and releasing the brake pedal may result in

A. a loss of brake air pressure

B. a build up of brake air pressure

C. no change in brake air pressure

Back 17

A. a loss of brake air pressure

Front 18

what is emergency controlled braking

A. you apply the brakes as hard as you can without locking the wheels

B. you brake as hard as you can release the brakes when the wheels lock and reapply the brakes when the wheels start rolling

C. you apply the hand valve for one second, then push hard on the brake pedal.

Back 18

A. you apply the brakes as hard as you can without locking the wheels

Front 19

the application pressure gauge shows how much air pressure you

A. have in the air tanks

B. have in the modulating control valve

C. are applying to the brakes

Back 19

C. are applying to the brakes

Front 20

when you apply the brakes. the brake shoes/ linings are pressed agaist the

A. brake drum or disc

B. slack adjuster

C. s- cam

Back 20

A. brake drum or disc

Front 21

in air brake vehicles the parking brakes should be used

A. as little as possible

B. to hold your speed when going downhill

C. any time the vehicle is parked

Back 21

C. anytime the vehicle is parked

Front 22

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

A. wedge drum

B. s- cam drum

C. disc brake

Back 22

B. s- cam drum

Front 23

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

A. only when driving down a hill

B. only on slippery roads

C. never

Back 23

C. never

Front 24

how should you check tat the trailer brakes come on when air pressure in the system drops below a certain level

A. park on a slight incline drain off air pressure, set parking brakes and check for movement.

B. chock the wheels apply the parking brake shut the engine off and pump the brake pedal to reduce air tank pressure

C. wait for normal air pressure release the parking brake move the truck forward slowly and apply the brake pedal firmly

Back 24

B. chock the wheels apply the parking brake shut the engine off and pump the brake pedal to reduce air tank pressure.

Front 25

you should know your brakes are fading when

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

B. the brake pedal feels spongy when you apply pressure

C. your speed increases when you reduce pressure on your brake pedal.

Back 25

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

Front 26

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

A. 1psi in one minute

B. 2psi in one minute

C. 3 psi in one minute

Back 26

C. 3 psi in one minute

Front 27

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 linkages.

Back 27

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

Front 28

truck and bus parking or emergency brakes must be held on by

A. air pressure

B. a modulating control valve

C. mechanical force

Back 28

C. mechanical force

Front 29

the air brake lag distance at 55mph on dry pavement adds about ___ feet to your stopping distance

A. 12

B. 32

C. 52

Back 29

B. 32

Front 30

what is emergency controlled braking

A. you apply the brakes as hard as you can without locking the wheels

B. you brake as hard as you can release the brakes when the wheels lock and reapply the brakes when the wheels start rolling.

C. apply the had valve for one second then push the brake pedal hard

Back 30

A. you apply the brakes as hard as you can without locking wheels

Front 31

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

Back 31

B. 60

Front 32

for air brake systems in good condition the air compressor should start pumping at about ___ psi

A. 100

B. 125

C. 150

Back 32

A100

Front 33

if your truck has a dual air system and one of the systems is low on pressure

A. the brake drums will not be fully pressurized

B. either the front or rear brakes will not be fully operational

C. the manual slack adjusters on the s cam brakes are not set properly

Back 33

B. either the front or rear brakes will not be fully operational

Front 34

the air compressor governor controls

A. when air is pumped into the air tanks

B. the speed of the air compressor

C. air pressure applied to the brakes

Back 34

A. when air is pumped into the air tanks

Front 35

if your truck or bus had 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 spring emergency parking brakes to move a short distance

Back 35

C. release spring emergency parking brakes to move a short distance.

Front 36

if your trucks air compressor has its own oil supply when should you first check the oil level

A. during your first en route inspection

B. immediately after stopping

C. before driving

Back 36

C. before driving

Front 37

the stop light switch

A. turns on the brake light to warn drivers behind you

B. tells you when you need to use your emergency brakes

C. tells you when the air brake system is low on air pressure.

Back 37

A. turns on the brake light to warn drivers behind you

Front 38

you are on a steep downgrade and have reached your safe speed of 40 mph you would apply the service brakes until your speed drops to _____mph

A. 25

B. 30

C. 35

Back 38

C. 35

Front 39

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 people .

Back 39

A. depends on the service brakes being in adjustment.

Front 40

the brake system that applies and releases some brakes when the driver uses the brake pedal is the

A. emergency

B. service

C. parking

Back 40

B. service

Front 41

under normal conditions to engage the parking brakes the driver must first

A. turn off the engine only

B. let the air out of the air brake system

C. be sure that the air brake system is fully pressurized

Back 41

B. let the air out of the air brake system

Front 42

before driving a truck or bus with a dual air brake system the pressure in each system should be at lease ___ psi

A. 80

B. 100

C. 120

Back 42

B. 100

Front 43

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

A. spring pressure

B. air pressure

C. hydraulic pressure

Back 43

A. spring pressure

Front 44

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

A. 50

B. 60

C. 80

Back 44

B. 60

Front 45

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

A. 1

B. 3

C. 2

Back 45

C. 2

Front 46

the proper method of braking when going down long and or steep grades after selecting the proper gear is to brake until your speed is about ____ miles per hour below your safe speed then release your brakes

A. 5

B. 10

C. 15

Back 46

A. 5

Front 47

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

A. chock the wheels and turn off the parking brakes

B. with the parking brake and then apply the service brake

C. and drain off air pressure before adjusting vehicle movement

Back 47

A. chock the wheels and turn off the parking brakes

Front 48

some air brake systems have an alcohol evaporator what may happen if you don't keep the unit filled alcohol

A. the scam may not rotate back when you release the brake pedal

B. ice may form in the air storage tanks and cause the brakes to fail

C. ice may form on the brake drums and warp them

Back 48

B. ice may form in the air storage tanks and cause the brakes to fail

Front 49

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. connects the slack adjusters by a series of rods and linkages

Back 49

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

Front 50

total stopping distance for vehicles with air brakes is longer than that for vehicles with hydraulic brakes due to ____ distance

A. brake lag

B.reaction

C> effective braking

Back 50

A. brake lag

Front 51

the air compressor governor controls

A. the speed of the air compressor

B. air pressure applied to the brakes

C. when air is pumped into the air tanks

Back 51

C. when air is pumped into the air tanks

Front 52

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

A. when you will only be stopped for less than one hour

B. when you are going to test the parking brake

C. when you come down a steep grade and your brakes are very hot

Back 52

C. when you come down a steep grade and your brakes are very hot

Front 53

excessive use of the service brakes results in overheating which can lead to

A. improper adjustment of the s-cam

B. increased contact between the brake drums and brake linings

C. expansion of the brake drums

Back 53

C. expansion of the brake drums

Front 54

if air pressure does not build up to normal within the correct amount of time

A. you should be ready to use your parking brake to help stop

B. the alcohol container may be low

C. your air pressure may drop too low during driving

Back 54

C. your air pressure may drop too low during driving