Lull 944E-42 Service Manual - Manual (Page 229)

10-17 944E-42
Stabil-TRAK™ System
10.5.6 Hydraulic Circuit Operation - Free Pivot Mode, Base Oil Out
Conditions:
• Boom angle is below 40°
• Rear axle pivots freely
• Travel select lever in (F) FORWARD or (R) REVERSE
position
• Park brake OFF
• Service brake DISENGAGED
Operation:
When the conditions are met, solenoids 12A and 12B are
energized. As the left side of the rear axle moves down,
the rod is forced up, forcing hydraulic oil out from the base
end of the stabilizer cylinder (1). The oil then flows through
the solenoid-operated valves 12A (2) and back through
solenoid-operated valve 12B (3), to the rod side of the
stabilizer cylinder.
Because the volume of oil needed on the rod side is less
than that needed on the base side, excess oil is returned
to the tank through a 100 psi (7 bar) reducing cartridge (4)
in the Stabil-TRAK™ manifold.
MU4762
HYDRAULIC
RESERVOIR
ACCUMULATOR
CHARGE/SECONDARY
FUNCTION VALVE
LS
DRAIN P1
LSG ACR
SW P
ACF EF CF PIL PB
PBG
PPG
SW
HYDRAULIC OIL
COOLER
FRAME SWAY
JOYSTICK
CHECK
VALVE
FITTING
CHECK
VALVE
FITTING
Ø .041
P
T
2 1
ATTACH
TILT
FRAME EXT/RET LFT/LWR
AU
X
TRANS
MAIN CONTROL
VALVE
INLET
OUTLET
PUMP
Ø .048
SOLENOID COIL
STATE
ENERGIZED
DE-ENERGIZED
E
DE
Suction
Return
Load Sense
Pressure
Pilot Pressure
STABILIZER
CYLINDER
.060 DIA.
FTR
P
T
V G3 G2
G1
4A 4B 12B
3
2B
2A
12A
.060 DIA.
.030 DIA.
100 PSI
STABIL-TRAK TM
MANIFOLD
DE
E DE E DE
FRAME
SWAY
CYLINDER
FTR
FTB
200
PSI
2
3
1
4