SkyTrak 8042 Service Manual - Manual (Page 881)

Stabil-TRAK™ System and Boom Interlock System
10.40 Model 8042, 10042, 10054 Legacy Rev. 10/03
10.12.5 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 Stabil-TRAK™ cylinder (1). The oil then flows
through the solenoid-operated valves 12A (2) and
12B (3), to the rod side of the Stabil-TRAK™ 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.
FTR
P
T
V
Pressure
Suction
Return
Load Sense
G3 G2
G1
4A 4B 12B
3
2B
2A
12A
FRAME
SWAY
CYLINDER
.060 DIA.
.030 DIA.
.060 DIA.
100 PSI
SOLENOID COIL
STATE
ENERGIZED
DE-ENERGIZED DE
E
DE
E E DE DE
P
T
C
PS PB
PLT
PSG
PBG
G
IN T
T
AT
TA
C
H
TIL
T
P
FRAME SWAY EXT/
RET
LFT/
LW
R
AU
X
STABIL-TRAK
MANIFOLD
TM
STABIL-TRAK
CYLINDER
TM
HYDRAULIC
OIL COOLER
HYDRAULIC
RESERVOIR
SECONDARY
FUNCTION
MANIFOLD
PUMP
MAIN CONTROL
VALVE
BYPASS
CHECK
VALVE
BYPASS
CHECK
VALVE
MH3061
1
2
3
4