Lull 944E-42 Service Manual - Manual (Page 330)

Hydraulic System
8.78 Model 644E-42/944E-42 Rev. 6/04
8.8.12 Boom Retract Circuit & Troubleshooting (Dual Joystick)
(Refer to Section 8.8.51, “Boom Extend/Retract Circuit Description (Dual Joystick),” for a more detailed
explanation of this circuit.)
Suction
Return
Load Sense
Pressure
Pilot Pressure
PUMP
HYDRAULIC
RESERVOIR
ATTACH
TILT
FRAME
EXT/RET LFT/LWR
AU
X
TRANS
ACCUMULATOR
CHARGE/SECONDARY
FUNCTION VALVE
LS
DRAIN P1
LSG ACR
SW P
ACF EF CF PIL PB
PBG
PPG
SW
INLET
OUTLET
HYDRAULIC OIL
COOLER
REAR JOYSTICK
3
4
T
P
2 1
CHECK VALVE
85 PSI (5,9 bar)
EXTEND/RETRACT
CYLINDER
R E
RETURN
FILTER
25 PSI
(1,7 BAR)
BYPASS
CHECK
VALVE
MAIN
CONTROL
VALVE
MU0571
Pressure
Reducing
Cartridge
Main
Relief
Valve
“PPG”
Pressure
Tap
Implement
Pump Pressure
Tap
Pilot Supply
Line
Unloader
Cartridge