190105cA truck/tractor air brake system components - part A

Question 1

what’s the purpose of a dual air brake system?

pg.2

Answer 1

greater safety incase one service circuit false

pg.2

Question 2

witch supply tank operates steering axle and witch operates drive axle?
pg.2

Answer 2

primary circuit operates = drive axle(s)
secondary circuit operates = steer axle
pg.2

Question 3

what are the 5 basic circuits? name there colors

pg.2

Answer 3

• supply [blue]
• primary [green]
• secondary [red]
• parking/emergency brake circuit [orange]
• trailer control circuit [unknown]
  pg. 2

Question 4

what’s the purpose of the supply circuit?

pg.3

Answer 4

• provide brakes and accessories with clean dry air
• maintain system pressure
  pg. 3

Question 5

what are the components in a the supply circuit

pg.3

Answer 5

• compressor
• posture and contamination control
• reservoirs
• governor
  pg. 3

Question 6

what are 2 common types of compressors?

what is the more common type of driving an air compressor?

compressor output unit is___
pg.4

Answer 6

• single stage
• reciprocating type
• gear drive
• cfm
  pg. 4

Question 7

what are the 2 valves and 1 piston i need to remember from the compressor?
pg.5

Answer 7

• discharge valve
• inlet valve
• unloader piston/plunger
  pg. 5

Question 8

compressor has 2 cycles, what are they?

pg.6

Answer 8

• unloaded cycle
• loaded cycle
  pg. 6

Question 9

compressor kick out pressure is?
compressor kick in pressure is?
pg.8, 12

Answer 9

115 - 135 psi
25 psi less then kick out
pg.8, 12

Question 10

governor pressure adjusting spring, adjusting screw and locknut is to adjust what?
pg.9

Answer 10

kick out pressure

pg.9

Question 11

what’s the 3 ports in a compressor governor?

pg.9

Answer 11

• exhaust (EXH)
• unloader (UNL)
• reservoir (RES)
  pg. 9

Question 12

water and oil in the system causes what?

pg.12

Answer 12

• in the winter water freezes and causes brake malfunctions
• water and oil mix, creating slush, causing valves to stick
  pg. 12

Question 13

what material is inside an air dryer cartridge? and what do they do with moisture?
pg.19

Answer 13

desiccant material and they suspend moisture and moisture vapour
pg.19

Question 14

acronym for supply port and delivery port

pg.19

Answer 14

• SUP (supply port)
• DEL (delivery port)
  pg. 19

Question 15

how big most the reservoirs be?

pg.20

Answer 15

atlas 12 times the combined volume of the brake chamber on the unit
pg.20

Question 16

pressure reservoirs must be hydrostatically tested to _____

pg.20

Answer 16

5 times the related working pressure

pg.20

Question 17

what is the purpose of a supply reservoir?

pg.23

Answer 17

• supply additional air volume
• be a final place for moisture to settle
  pg. 23

Question 18

purpose of a check valve at primary and secondary resevoirs?

pg.23

Answer 18

ensures at least one service reservoir remains charged in the even that the other loses air pressure
pg.23

Question 19

what’s the safety valve for?
where can it be located?
at what pressure does the safety valve vent at?
how do you check safety valve operations?
pg.24

Answer 19

• incase the governor fails it prevents the system from over pressurizing
• compressor, air dryer and supply reservoir (most common)
• 150 psi
• pull on the pin
  pg. 23

Question 20

what type of gauge is used to determine reservoirs pressure?
witch reservoirs need a pressure gauge?
pg.25

Answer 20

• dual-needle pressure gauge
• primary res and secondary res
  pg. 25

Question 21

how does a low pressure warning device work?

pg.26

Answer 21

when pressure drops in the primary and/or secondary to 60 or less a visual and audible devise warns the driver.
(now a days it goes off at 68-74 psi)
pg.26

Question 22

what size must tubing, hoses and fitting can they be replaced with? what type of threads are most common?
pg.27

Answer 22

THE SAME SIEZE. NPT

pg.27

Question 23

what are air lines more commonly made of?

pg.28

Answer 23

nylon tubing

pg.28

Question 24

where can nylon tubing not be used?

pg.28

Answer 24

- where heat is above 93 C
       compressor discharge
- high wear, abrasion or movement is encountered
       vehicle frame to brake chambers
pg.28

Question 25

when talking about air brakes, what type of connection is more popular for steel tubing? why? pg.29

Answer 25

compression fittings, because flared connections are susceptible to fatigue from vibration pg.29

Question 26

flexible hose is used for? | pg.29

Answer 26

used to connect brake chambers | pg.29

Question 27

what type of hose is used for compressor discharge lines? | pg.29

Answer 27

hoses with extruded teflon inner cores and outer stainless steel braid pg.29

Question 28

what's the purpose of the primary service brake circuit? | pg.30

Answer 28

to allow the operator to control the application and release of the drive axle rakes pg.30

Question 29

primary service circuit consist of what components? | pg.31

Answer 29

- dual-circuit brake valves - relay valve - service brake chambers pg. 31

Question 30

purpose of the dual-circuit brake valve | pg.32

Answer 30

give the operator control of the brakes on the vehicle | pg.32

Question 31

3 things that brake valve allows the operator to do is? | pg.32

Answer 31

- apply the brakes - release the brakes - regulate brake application pg. 32

Question 32

types of dual circuit brake valves | pg.32

Answer 32

- treadle valve (floor mounted) - pedal valve ( firewall mounted) pg. 32

Question 33

what type of air does the dual-circuit brake valve deliver? | pg.34

Answer 33

signal air to the service relay | pg.34

Question 34

when the dual-circuit brake valve is released, applied and balanced. what are the inlet and exhaust ports doing? pg.36

Answer 34

released = inlet CLOSED and exhaust OPEN applied = inlet OPEN and exhaust CLOSED balanced = inlet CLOSED and exhaust CLOSED pg.36

Question 35

whats the purpose of the service relay valve and where would it be located? pg.38

Answer 35

- the purpose is to speed up application and release time. - it's located near the primary service brake chambers pg. 38

Question 36

how does the service relay work? | pg.38

Answer 36

- air volume will be supplied from the primary reservoir to the supply port of the service port - a signal line from the dual-circuit valve will connect to the control port of the service relay. this signal will activate the service relay small air amount controlling large air amount pg.38

Question 37

the amount of air that is required to get the relay valve piston to move downwards, close the exhaust valve and open the inlet valve is called? pg.41

Answer 37

cracking pressure | pg.41

Question 38

what's the function of the service brake chamber? shortly describe it it works? pg.44

Answer 38

- to convert the energy of the compressed air into mechanical energy. - compressed air enters and pushes on the diaphragm tp apply the brakes - the return spring on the brake shoes and the return inside the brake chamber return the pushrod pg. 44

Question 39

whats the purpose of the secondary service circuit? | pg.46

Answer 39

to allow the operator to control the application and release of the steer axle brakes pg.47

Question 40

what's included in the secondary service circuit components? | pg.47

Answer 40

- dual-circuit brake valve - quick release valve - modulator valve - steer axle service brake chambers pg. 47