SkyTrak 8042 Service Manual - Manual (Page 879)

Stabil-TRAK™ System and Boom Interlock System
10.38 Model 8042, 10042, 10054 Legacy Rev. 10/03
10.12.3 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 Stabil-TRAK™ cylinder (1). The oil then flows
through the solenoid-operated valves 12B (2) and
12A (3), to the base side of the Stabil-TRAK™ 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.
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
STABIL-TRAK
CYLINDER
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
TM
HYDRAULIC
OIL COOLER
HYDRAULIC
RESERVOIR
SECONDARY
FUNCTION
MANIFOLD
PUMP
MAIN CONTROL
VALVE
BYPASS
CHECK
VALVE
BYPASS
CHECK
VALVE
MH3051
1
2
3
4