JLG 600A - Variable Displacement Pump (M46 Series)

SECTION 5 - HYDRAULICS
3121201 – JLG Lift – 5-27
5.6 VARIABLE DISPLACEMENT PUMP (M46
SERIES)
Troubleshooting
GAUGE INSTALLATION
It will be necessary to install a high pressure gauge into
the system pressure gauge ports to check the setting of
the high pressure relief valves.
Measuring the charge pump inlet vacuum will help locate
restrictions in the inlet lines, filter, etc.
Case pressure readings can help locate restrictions in the
return lines, oil cooler, and return filter.
Gauge Information
M1 System Pressure
Por t A
10, 000 PSI or 600 Bar Gauge
9/16-18 O-ring Fitting
M2 System Pressure
Por t B
10, 000 PSI or 600 Bar Gauge
9/16-18 O-ring Fitting
M3 Charge Pressure 1000 PSI or 60 Bar Gauge
9/16-18 O-ring Fitting or Tee into
Charge Pressure Filter Outlet Line
L1
L2
Case Pressure 1000 PSI or 60 Bar Gauge
1-1/16-12 O-ring Fitting
S Charge Pump Inlet
Vacuum
Vacuum Gauge
Tee into Charge Pump Inlet Line
M4 Servo Pressure 1000 PSI or 60 Bar Gauge
9/16-18 O-ring Fitting
M5 Servo Pressure 1000 PSI or 60 Bar Gauge
9/16-18 O-ring Fitting
Figure 5-29. Troubleshooting - Neutral Difficult or Impossible to Find