Pump - Kubota U20-3 Workshop Manual

U20-3, U25-3 WSM
c. Pump
Problem
1. The engine gets overloaded.
2. The pump flowrate drops
extremely with too low
discharge pressure.
3. Unusual noise or unusual
vibrations occur (cavitation
phenomenon).
4. There is oil leak.
Cause
1) Engine rpm higher than specified.
2) Pressure higher than specified.
3) Pump internal parts seized or damaged.
1) Engine rpm too low.
2) Pump coupling defective.
3) Pump internal parts seized or damaged.
1) Air or water mixed in hydraulic oil.
2) Suction strainer clogged.
3) Suction pipe clogged or throttled.
4) Attached pump in trouble (if provided).
5) Piston shoe poorly crimped.
6) Pump loosely mounted.
7) Coupling defective.
1) O-ring or sheet packing defective.
2) Oil leak from oil seal edge.
IV-S-6
Hydraulic system (Service section)
Correction
1) Readjust as specified.
2) Readjust as specified.
3) repair or replace the pump.
1) Readjust the rpm.
2) Repair or replace the pump coupling.
3) Repair or replace the pump.
1) Retighten the circuit connections, the
suction pipe in particular. Replace if
water is mixed in.
2) Clean or replace the suction strainer.
3) Correct the suction pipe.
4) Repair or replace the attached pump.
5) Replace the piston assembly.
6) Mount correctly.
7) Replace the coupling.
1) Replace the O-ring or sheet packing
(install as specified).
2) Replace or repair the oil seal or shaft.