Drive Pump - Genie GS-3390 Service Manual

Section 4 • Repair Procedures
HYDRAULIC PUMPS
6-2

Drive Pump

The drive pump is a bi-directional variable
displacement piston pump. The pump output is
controlled by the electronic displacement controller
(EDC), located on the pump. The only adjustment
that can be made to the pump is the neutral or null
adjustment. Any internal service to the pump
should only be performed at an authorized
Sundstrand-Sauer service center. Contact the
Genie Industries Service Department to locate
your local authorized service center.
How to Remove the Drive Pump
Component damage hazard. The
work area and surfaces where this
procedure will be performed must
be clean and free of debris that
could get into the hydraulic system
and cause severe component
damage. Dealer service is
recommended.
Note: When removing a hose assembly or fitting,
the O-ring on the fitting and/or hose end must be
replaced and then torqued to specification during
installation. Refer to Section Two, Hydraulic Hose
and Fitting Torque Specifications.
1 Remove the lift/steer pump. See 6-1, How to
Remove the Lift/Steer Pump.
2 Disconnect the electrical connections at the
EDC located on the drive pump.
4 - 88
3 Tag, disconnect and plug the hydraulic hoses
from the drive pump. Cap the fittings on the
pump.
4 Support the drive pump with a suitable lifting
device and remove the two drive pump
mounting fasteners.
5 Carefully pull the drive pump out until the pump
coupler separates from the flex plate.
6 Remove the drive pump from the machine.
Note: Before installing the pump, verify proper
pump coupler spacing. See 4-3, Flex Plate .
Models with hydraulic tank shut-off valves:
Models without hydraulic tank shut-off valves:
GS-3390 • GS-4390 • GS-5390
Bodily injury hazard. Spraying
hydraulic oil can penetrate and
burn skin. Loosen hydraulic
connections very slowly to allow
the oil pressure to dissipate
gradually. Do not allow oil to
squirt or spray.
Component damage hazard. The
hydraulic pump may become
unbalanced and fall if not properly
supported when removed from the
machine.
Component damage hazard.
When installing the pump, do not
force the pump coupler into the
flexplate or damage to the pump
shaft seal may occur.
Component damage hazard. Be
sure to open the two hydraulic
tank valves and prime the pump
after installing the pump.
Component damage hazard. Be
sure to fill the hydraulic tank to
specification and prime the pump
after installing the pump.
Part No. 72863
July 2007
REV D