JLG 740A, Service And Maintenance Manual

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SECTION 3 - CHASSIS & TURNTABLE
3-42 – JLG Lift – 3121160
20. Install orifice poppet (30).
21. Install shift spool (31).
22. Install spring retaining washers onto springs (32 and
33).
23. Carefully install centering springs (34, 35, and 36).
24. Install new O-rings (37, 38, and 39).
25. Using a 5/8 in wrench torque plug (40) to 20 ft.lbs.
(27 Nm).
26. Using a 11/16 in wrench, torque plugs (41 and 42) to
27 ft.lbs. (37 Nm).
Initial Start-up Procedures
Follow this procedure when starting-up a new motor or
when installing a motor that has been removed.
Prior to installing the motor, inspect for damage incurred
during shipping. Make certain all system components
(reservoir, hoses, valves, fittings, heat exchanger, etc.) are
clean prior to filling with fluid.
1. Fill the reservoir with recommended hydraulic fluid.
Always filter fluid through a 10 micron filter when
pouring into the reservoir. Never reuse hydraulic
fluid.
2. Fill the inlet line leading from the pump to the reser-
voir. Check the inlet line for properly tightened fit-
tings and be certain it is free of restrictions and air
leaks.
3. Fill the pump and motor housing with clean hydrau-
lic fluid. Pour filtered oil directly into the upper most
case drain port.
4. To ensure the pump and motor stay filled with oil,
install case drain lines into the upper most case
drain ports.
5. Install a 0 to 500 psi (0 to 35 bar) gauge in the
charge pressure gauge port of the pump to monitor
system pressure during start up.
6. While watching the pressure gauge, run the engine
at the lowest possible speed until system pressure
builds to normal levels (minimum 160 psi [11 bar]).
Once system pressure is established, increase to full
operating speed. If system pressure is not main-
tained, shut down the prime mover, determine
cause, and take corrective action.
7. Operate the hydraulic system for at least fifteen min-
utes under light load conditions.
8. Check and adjust control settings as necessary after
installation.
9. Shut down the prime mover and remove the pres-
sure gauge. Replace plug at the charge pressure
gauge port.
10. Check the fluid level in the reservoir; add clean fil-
tered fluid if necessary. The motor is now ready for
operation.
39
40
34
30
41
37
36
33
42
38
35
32
31
(27 Nm)
20 ft.lbs.
5/8 in
(37 Nm)
(37 Nm)
27 ft.lbs.
27 ft.lbs.
11/16 in
11/16 in
30. Orifice Poppet
31. Shift Spool
32. Spring
33. Spring 34. Spring
35. Spring
36. Spring 37. O-ring
38. O-ring
39. O-ring 40. Plug
41. Plug
42. Plug
Figure 3-32. Loop Flushing Spool