Lull 944E-42 Service Manual User Manual
Page 227
10-15
944E-42
Stabil-TRAK™ System
10.5.4
Hydraulic Circuit Operation - Free Pivot Mode, Rod 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 extends, forcing hydraulic oil out from the rod end
of the stabilizer cylinder (1). The oil then flows through the
solenoid-operated valve 12B (2) and back through
solenoid-operated valve 12A (3), to the base side of the
stabilizer cylinder.
Because the volume of oil needed on the base side is
greater than that needed on the rod side, the extra oil
needed is supplied from the main hydraulic system
through a 100 psi (7 bar) reducing cartridge (4) in the
Stabil-TRAK™ manifold.
MU4512
Suction
Return
Load Sense
Pressure
Pilot Pressure
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
FRAME
SWAY
CYLINDER
FTR
FTB
SOLENOID COIL
STATE
ENERGIZED
DE-ENERGIZED
E
DE
Ø .041
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
P
T
2
1
ATTACH
TILT
FRAME
EXT/RET
LFT/LWR
AU
X
TRANS
MAIN CONTROL
VALVE
INLET
OUTLET
PUMP
Ø .048
200
PSI
2
3
1
4