TROUBLESHOOTING
PISTON PUMP
1
5
PISTON PUMP 5I0AQ00
PISTON PUMP
Symptoms Major causes Remedies
Noise is too loud, unusual
sound is heard
⢠Suction hose is crushed or suction filter
is clogged.
⢠Remove the dirt and correct the crushing.
⢠Joint in the suction side is loose and
sucking air.
⢠Retighten each joint.
⢠Cavitation is being produced due to too
high viscosity of the hydraulic oil.
⢠Replace with hydraulic oil of proper viscos-
ity.
⢠Pump and engine are not center
aligned.
⢠Center them again.
⢠Frothing of hydraulic oil. ⢠Investigate the cause of frothing and cor-
rect it.
⢠Engine RPM is too high. ⢠Run at the rated RPM.
⢠Mechanical damage to the parts (e.g.,
bearing).
⢠Replace the damaged part(s) or the pump.
Discharge is insufficient ⢠Engine RPM is too low. ⢠Run at the rated RPM.
⢠Oil temperature is too high. ⢠Stop running, and check the temperature
again after the oil cools down.
⢠Viscosity of hydraulic oil is too high. ⢠Replace with hydraulic oil of proper viscos-
ity.
⢠Pump volume efficiency becomes low. ⢠Replace the pump.
⢠Hydraulic oil tank level is too low. ⢠Add oil to the specified level.
⢠Clogging in the suction piping or the
suction filter.
⢠Clean the piping.
⢠Leak volume of hydraulic devices other
than the pump is increased.
⢠Repair or replace the leaking hydraulic de-
vice.
Pressure is not increased ⢠Set pressure for the relief valve drops. ⢠Set the relief valve pressure again.
⢠Leak volume of hydraulic devices other
than the pump is increased.
⢠Repair or replace the leaking hydraulic de-
vice.
⢠Pump volume efficiency becomes low. ⢠Replace the pump.
Abnormal heat is generat-
ed
⢠Leak volume from the pump is in-
creased.
⢠Replace the pump.
⢠Mechanical damage to the parts (e.g.,
bearing).
⢠Replace the damaged part(s) or the pump.
⢠Seizing on the sliding part. ⢠Replace the damaged part(s) or the pump.
Oil leak ⢠Seals are damaged. ⢠Replace the seal(s).
⢠Sliding part between the shaft and the
oil seal is worn out.
⢠Replace the shaft or the pump.
⢠Plugs and bolts are loosened. ⢠Retighten the plugs and bolts, or replace
the seals.