JLG 340AJ Service Manual - Manual (Page 228)

SECTION 5 - HYDRAULICS
5-70 – JLG Lift – 3121259
Removing the Pump
Before working on the pump, thoroughly clean the outside. If
the pump has an auxiliary pump attached, remove both
pumps as a single unit. Tag and cap all hydraulic lines as they
are disconnected, and plug all open ports to ensure that dirt
and contamination do not get into the system.
CONTAMINATION CAN DAMAGE INTERNAL COMPONENTS AND VOID THE MAN-
UFACTURER'S WARRANTY. TAKE PRECAUTIONS TO ENSURE SYSTEM CLEANLI-
NESS WHEN REMOVING AND INSTALLING SYSTEM LINES.
DISASSEMBLY, INSPECTION, ASSEMBLY
1. With the prime mover off, thoroughly clean all dirt and
grime from the outside of the pump.
2. Tag, disconnect, and cap each hydraulic line connected
to the pump. As hydraulic lines are disconnected, plug
each open port, to ensure that dirt and contamination
do not get into the pump.
3. Remove the pump and its auxiliary pump (if applicable)
as a single unit.
NOTE: Be careful, do not damage solenoids and electrical connec-
tions when using straps or chains to support the pump.
4. Ensure the work surface and surrounding area are clean
and free of contaminants such as dirt and grime.
5. Inspect the system for contamination.
6. Look at the hydraulic fluid for signs of system contami-
nation, oil discoloration, foam in the oil, sludge, or metal
particles.
7. Before replacing the pump, replace all filters and drain
the hydraulic system. Flush the system lines and fill the
reservoir with the correct, filtered hydraulic fluid.
8. Fill the pump with clean, filtered hydraulic fluid.
9. Attach the pump to the prime mover. Torque mounting
screws according to the manufacturers recommenda-
tion.
10. Replace all hydraulic lines. Ensure the charge inlet line is
filled with fluid.
Electric Control Module
NOTE: Remove plug on top of control to ensure the swashplate
feedback pin is properly positioned in the center of the con-
trol module when installing control.
REMOVAL, INSPECTION, REASSEMBLY
Refer to Figure 5-37., Control Module Removal/Installation.
1. Using a 5 mm internal hex wrench, remove the six cap
screws (D250).
2. Remove the control module and gasket (D150). Discard
the gasket.
3. If necessary, remove orifices (F100) using a 3 mm inter-
nal hex wrench. Tag and number them for reinstallation.
4. Inspect the machined surfaces on the control and top of
the pump. If you find any nicks or scratches, replace the
component.
NOTE: Ensure you install dowel pins (D300) in housing before
installing control.
5. Install a new gasket (D150).
6. If you removed screen (D084), install a new one. Install
with the mesh facing outward (see drawing).
7. If previously removed, install orifices (F100) using a 3
mm internal hex wrench. Torque to 2.5 Nm [1.8 lb.ft.].
8. Install the control module and six cap screws (D250).
9. Using a 5 mm internal hex wrench, torque the cap
screws (D250) to 13.5 Nm [10 lb.ft.].