Air Brakes

Question 1

a low air pressure warning signal should activate

Answer 1

when tank pressure falls below 55 psi

Question 2

why should you regularly drain the air tanks

Answer 2

because compressed air contains some water and the water collects in the tanks

Question 3

vehicles equipped with anti-lock braking systems (ABS) have ___ malfunctioning lamps to indicate when the ABS is not working

Answer 3

yellow

Question 4

a dual air brake system

Answer 4

consist of two separate air brake systems that share a single set of controls.

Question 5

the safety valve is set to open up at ____ pounds per square inch (psi)

Answer 5

150

Question 6

air pressure should build up in a single air system within

Answer 6

3 minutes

Question 7

some air brake systems use alcohol

Answer 7

to reduce the risk of ice forming in air brake valves

Question 8

spring breaks come on

Answer 8

when too much air pressure is lost.

Question 9

on trucks and buses where are ABS malfunction lamps located?

Answer 9

on the instrument panel.

Question 10

before driving a vehicle with dual air brake systems you must wait for the air compressor to build a minimum of ____ in both the primary and secondary systems

Answer 10

100 PSI

Question 11

anti-lock braking systems (ABS)

Answer 11

are equipped in addition to other braking systems and do not reduce normal braking power.

Question 12

if using air tanks with manual operated drains how often should you drain the tanks

Answer 12

every day

Question 13

the parking brake should be

Answer 13

use whenever you park your vehicle.

Question 14

if the brake pads rub against the brake drums and create too much heat

Answer 14

the brakes may stop working.

Question 15

a low air pressure warning signal

Answer 15

is required on vehicles with air brakes

Question 16

foundation brakes are used

Answer 16

at each wheel

Question 17

the air compressor governor controls

Answer 17

when the air compressor pumps air into the air storage tanks

Question 18

when traveling down a steep downgrade

Answer 18

shift into a lower gear then use brakes to supplement the breaking effort of the engine.

Question 19

to confirm that the trailer has ABS you can

Answer 19

look under the trailer for wheel speed sensors coming from the back of the brakes.

Question 20

dollies equipped with abs are required to have malfunction lamps located

Answer 20

on the left side

Question 21

The ___ tell the driver how much pressure is in the air brakes

Answer 21

supply pressure gauge

Question 22

when inspecting your brakes a slack adjuster should move ____ from where it is attached to the push rod

Answer 22

no more than one inch

Question 23

before driving a vehicle with air brakes you should ensure that the spring breaks come on automatically when

Answer 23

air pressure falls below 45 PSI

Question 24

during an applied leakage test the maximum leakage rate of a double combination vehicle is

Answer 24

4 psi in a minute

Question 25

during an applied leakage test the maximum leakage rate for a triple combination vehicle is

Answer 25

6 psi I in a minute

Question 26

front wheel breaking works

Answer 26

under all conditions

Question 27

when you press the brake pedal in a vehicle with s-cam brakes air pressure pushes out the rod and moves the

Answer 27

slack adjuster

Question 28

friction inside a brake drums is caused when the brake shoes and linings

Answer 28

push against the inside of the drum.

Question 29

breaking mechanisms are located ____ a brake drum

Answer 29

inside

Question 30

when a brake pedal is pressed and the s-cam is turned, the s-cam

Answer 30

princess the brake shoes against the inside of the brake drum

Question 31

to inspect slack adjusters on s-cam brakes you need to

Answer 31

chock the wheels and disengage the parking brake

Question 32

how should you test the low pressure warning signal

Answer 32

rapidly press and release the brake pedal

Question 33

before starting down a hill be sure to

Answer 33

switch into a low gear.

Question 34

during the applied leakage test the maximum leakage rate for a single vehicle with air brakes is

Answer 34

3 psiI in one minute

Question 35

during a static leakage test the maximum leakage rate for a double combination vehicle is

Answer 35

3 psii in one minute

Question 36

during a static leakage test the maximum leakage rate for a triple combination vehicle with air brakes is ___ in a minute

Answer 36

5 psi

Question 37

during a static leakage test the maximum leakage rate for a single vehicle with air brakes is ___ in one minute

Answer 37

2 psi

Question 38

while driving spring breaks are generally held in place by

Answer 38

air pressure

Question 39

the emergency brake system uses

Answer 39

parts of both the parking in service brake systems.

Question 40

a modulating control valve can't control the

Answer 40

spring breaks

Question 41

during a walk around inspection ensure there are no cracks on the brake drums that are more than____ of with of the friction area

Answer 41

one half

Question 42

the air pressure in a dual air brake system should build up from 85 to 100 psi within

Answer 42

45 seconds

Question 43

in cold weather and alcohol evaporator should be checked and filled

Answer 43

every day

Question 44

applying the brake pedal causes air pressure to activate the electric switch and

Answer 44

turn on the brake lights

Question 45

a one-way check valve

Answer 45

prevents air from escaping if the air compressioner has a leak

Question 46

an air compressor governor will stop the compressor from pumping air once the air tanks have an air pressure level of

Answer 46

125 psi

Question 47

while driving downhill you should break until you reach a speed that is____ below your safe speed and then release the brake pedal

Answer 47

5 mph

Question 48

when you need to stop in an emergency you should

Answer 48

stop in a way that keeps your vehicle in a straight line.

Question 49

if breaking at a speed of 55 mph while driving on dry pavement the brake lag can add ____ to your vehicles total stopping distance

Answer 49

32 feet

Question 50

an air brake equipped vehicle traveling at a speed of 55 mph under ideal driver conditions we need approximately ____ to come to a complete stop

Answer 50

450 feet