Bulletin 947070-B
THE OILGEAR COMPANY
9
Irregular or
Unsteady Operation
Fluctuating load sense differential pressure.
Check system flow control valve/orifice.
Faulty control piston (19), sequence valve (54) or PC control
cartridge (55) operation.
Inspect components. Replace.
Fluid level in reservoir is low or supercharge is insufficient.
Verify fluid level and/or supercharge.
Air entering hydraulic system.
Inspect system for leak.
Low viscosity fluid used.
Increase size of OP2. Refer to Table 4.
Remote PC setting close to pump PC setting.
Increase pump PC setting.
Worn axial piston pump.
Inspect components. Replace.
Faulty output circuit components (cylinder, motors, valves or
other related components).
Inspect components. Replace.
Loss of Pressure
Worn piston pump.
Inspect components. Replace.
Worn hydrobearing.
Worn or grooved cylinder barrel (38) and/or port plate (43)
mating surfaces.
Worn piston/shoe assemblies (39) or piston bores in cylinder.
Worn or broken saddle bearing (30).
Faulty output circuit components.
Excessive or High
Peak Pressure
Faulty output circuit components.
Check the relief valves.
Faulty PC control cartridge (55) operation.
Inspect components. Replace.
Seized control piston (19).
Worn or broken saddle bearing (30).
Inspect components. Replace.
Excessive Noise
Pump stopped or started incorrectly under load.
Verify operation procedure of pump.
Low fluid level in reservoir or insufficient supercharge causing
cavitation.
Verify fluid level and/or supercharge.
Air entering hydraulic system.
Inspect system for leak.
Fluid too cold or viscosity too high.
Verify fluid temperature and/or type.
Suction line problem i.e.; obstructions in line, line too long, line
diameter too small or too many bends and/or loops in line.
Inspect line and for obstruction.
Broken or worn piston/shoe assembly (39).
Inspect components. Replace.
Pump rotating in wrong direction.
Inspect operation direction of pump.
Excessive Heating
Operating pump above rated or peak pressure.
Verify pump limitations.
Low fluid level in reservoir or insufficient supercharge.
Verify fluid level and/or supercharge.
Air entering hydraulic system.
Inspect system for leak.
Worn piston pump.
Inspect components. Replace.
Worn or grooved cylinder barrel (38) and/or port plate (43)
mating surfaces.
Faulty output circuit components (continuous blowing relief valves
or "slip" through valves, cylinder or other components.
Insufficient cooling provision or clogged coolers.
Inspect for obstruction.
Insufficient case fluid level (wrong drain port).
Use highest drain port.
OP2 too big or missing causing excessive case drain.
Decrease size of OP2.
Sequence spool seized.
Inspect, replace spool and valve plate if necessary.
Sequence spool leaking (if heating occurring during
compensating).
TROUBLESHOOTING
PROBLEM
CAUSES
REMEDY