Domestic Series 7000 Hydraulics
18
8. HYDRAULIC LIFT CYLINDER AND CON-
TROL VALVE
8.1. If the hydraulic lift cylinder does not work or is
low on power, begin by making a visual inspec-
tion of the cylinder, linkage, and feedback rod.
See Figure 8.1.
8.2. If the lift cylinder is operable, run it through the
full range of travel to confirm that the feedback
rod is working correctly. Normal operating char-
acteristics include:
• The travel of the lift arms should be directly
related to the height of the lift arms.
• In all positions, the lift cylinder will apply only
upward force to the lift arms. It is a single-acting
cylinder.
• Downward travel is not under hydraulic force,
and is only caused by the weight of the lift arms
and any accessories mounted to them.
• At any point in their travel, the lift arms may be
manually lifted beyond the point that the hydrau-
lic system is holding them at. They will always
“float”.
• Because the steering system has priority over
the lift cylinder, it is normal for the lift cylinder to
have less power when the steering system is in
motion.
8.3. Orientation of the valve: See Figure 8.3.
8.4. Hydraulic Connections:
• The flexible line to the bottom of the valve pro-
vides pressure from the steering pump.
• A second flexible line leads back to the lift cylin-
der.
• The steel line leading from the top of the valve
forward directs fluid through the oil cooler, via
the return manifold, and back to the transmission
housing.
• Fluid is constantly circulating through this path,
from the steering pump, through the valve, then
to the return manifold.
• When the valve is actuated to raise the lift arms,
it redirects fluid from this path to the lift cylinder.
• When the valve is actuated to lower the lift arms,
fluid is allowed to empty from the lift cylinder
through the steel line leading from the top of the
valve to the transmission cover.
Figure 8.1
Lift
cylinder
Hydraulic line
from control valve
Feedback
rod
Figure 8.3
Hydraulic
line to cylinder
Hydraulic line
from
steering unit
Fluid return line
via: return manifold
and cooler
Return line directly to
transmission housing
(when arms are
owered
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