SECTION 5 - HYDRAULICS
3121259
– JLG Lift –
5-63
Table 5-13. Neutral Difficult or Impossible to Find
Item
Description
Action
Input to pump control
Input to control module is operating improperly
Disconnect input and check to see if pump comes back to
neutral. If Yes, input fault, replace/repair external control-
ler. If No, go to next step.
Pump control neutral
Neutral set improperly
Shunt servo gauge ports M4 and M5 together with exter-
nal hose and see if pump comes back to neutral. If Yes: con-
trol neutral improperly set (see page 35). If no: balance
swashplate (see Mechanical neutral adjustment, page
37). If you still cannot set neutral, replace control.
Table 5-14. Sluggish System Response
Item
Description
Action
Oil level in reservoir
Low oil level causes sluggish response
Fill reservoir.
High pressure relief valves/ pressure limiter settings
Incorrect pressure settings affects system reaction time
Adjust or replace high pressure relief valves.
Low prime mover speed
Low engine speed reduces system performance
Adjust engine speed.
Charge pressure
Incorrect pressure affects system performance
Measure and adjust charge pressure relief or replace
charge pump.
Air in system
Air in system produces sluggish system response
Fill tank to proper level. Cycle system slowly for several
minutes to remove air from system.
Contaminated control orifices
Control orifices are plugged
Clean control orifices.
Contaminated control screens
Control screens are plugged
Clean or replace control screens.
Pump inlet vacuum
Inlet vacuum is too high resulting in reduced system pres-
sure
Measure charge inlet vacuum. Inspect line for proper siz-
ing. Replace filter. Confirm proper bypass operation.
Summary of Contents for 340AJ
Page 1: ...Service and Maintenance Manual Model 340AJ P N 3121259 June 27 2017...
Page 2: ......
Page 10: ...vi JLG Lift 3121259 TABLE OF CONTENTS SECTION NO TITLE PAGE NO Thispageleftblankintentionally...
Page 15: ...3121259 JLG Lift xi LIST OF FIGURES FIGURE NO TITLE PAGE NO Thispageleftblankintentionally...
Page 18: ...xiv JLG Lift 3121259 LIST OF TABLES TABLE NO TITLE PAGE NO Thispageleftblankintentionally...
Page 42: ...SECTION 2 GENERAL 2 12 JLG Lift 3121259 NOTES...
Page 69: ...SECTION 3 CHASSIS TURNTABLE 3121259 JLG Lift 3 27 Figure 3 24 Bearing Pressing Tool...
Page 71: ...SECTION 3 CHASSIS TURNTABLE 3121259 JLG Lift 3 29 Figure 3 27 Bearing Nut Wrench...
Page 134: ...SECTION 3 CHASSIS TURNTABLE 3 92 JLG Lift 3121259 NOTES...
Page 157: ...SECTION 4 BOOM PLATFORM 3121259 JLG Lift 4 23 Figure 4 8 Rotator Counterbalance Valve...
Page 218: ...SECTION 5 HYDRAULICS 5 58 JLG Lift 3121259 Figure 5 32 Fasteners and Plugs Sheet 1 of 2...
Page 219: ...SECTION 5 HYDRAULICS 3121259 JLG Lift 5 59 Figure 5 33 Fasteners and Plugs Sheet 2 of 2...
Page 236: ...SECTION 5 HYDRAULICS 5 76 JLG Lift 3121259 Figure 5 39 Gear Pump Cutaway...
Page 246: ...SECTION 5 HYDRAULICS 5 86 JLG Lift 3121259 Figure 5 40 Oil Sampling Port...
Page 256: ...SECTION 6 JLG CONTROL SYSTEM 6 10 JLG Lift 3121259 Figure 6 3 Ground Module Sheet 1 of 4...
Page 273: ...SECTION 6 JLG CONTROL SYSTEM 3121259 JLG Lift 6 27 Figure 6 16 Analyzer Machine Setup Menu...
Page 274: ...SECTION 6 JLG CONTROL SYSTEM 6 28 JLG Lift 3121259 Figure 6 17 Analyzer Calibrations Menu...
Page 336: ...SECTION 6 JLG CONTROL SYSTEM 6 90 JLG Lift 3121259 NOTES...
Page 368: ...SECTION 7 BASIC ELECTRICAL INFORMATION SCHEMATICS 7 32 JLG Lift 3121259 NOTES...
Page 369: ......