Variable Displacement Pump (M46 Series); Troubleshooting - JLG 600A Service And Maintenance Manual

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.
Figure 5-29. Troubleshooting - Neutral Difficult or Impossible to Find
3121201
System Pressure
M1
Port A
System Pressure
M2
Port B
Charge Pressure
M3
Case Pressure
L1
L2
Charge Pump Inlet
S
Vacuum
Servo Pressure
M4
Servo Pressure
M5
– JLG Lift –
SECTION 5 - HYDRAULICS
Gauge Information
10, 000 PSI or 600 Bar Gauge
9/16-18 O-ring Fitting
10, 000 PSI or 600 Bar Gauge
9/16-18 O-ring Fitting
1000 PSI or 60 Bar Gauge
9/16-18 O-ring Fitting or Tee into
Charge Pressure Filter Outlet Line
1000 PSI or 60 Bar Gauge
1-1/16-12 O-ring Fitting
Vacuum Gauge
Tee into Charge Pump Inlet Line
1000 PSI or 60 Bar Gauge
9/16-18 O-ring Fitting
1000 PSI or 60 Bar Gauge
9/16-18 O-ring Fitting
5-27