Pump Component Trouble Causes And Remedy - Kubota KX080-3 Workshop Manual

WSM KX080-3 Service
e. Pump component trouble causes and remedy
(1) General precaution
The pump works normally for a long period of time as far as it is operated under appropriate condition.
If it will not work as planned, it is necessary first to check to see if the cause of trouble is derived from
either the pump itself or other equipment.
Although it is not easy to clarify the cause of trouble with hydraulic system, it is important to check and
investigate the following points and identify the location of abnormality.
1. Checking of filter
Check the filter element periodically. Check whether or not abnormal impurities are generated in large
amount. The cause of trouble may be predicted depending on the type of impurity.
2. Checking of drain oil
Check drain oil coming from the pump, motor etc. The cause of trouble can be predicted from drain
flowrate and type of impurity contained in drain oil.
3. Checking for abnormal noise and vibration.
Check various equipment for any abnormal noise and vibration.
Discovery of the source of abnormal noise and vibration leads to the clue of clarification of cause of
trouble.
4. Checking of pressure at various parts
Do not disassemble and check irrelevant equipment unnecessarily, but check the pressure by means
of pressure gauge and investigate the cause of trouble.
(2) Trouble shooting
Failure symptom
1. Pump will not discharge oil.
2. Pump discharge amount is small.
Circuit pressure will not be raised.
Suspected causes
1. Oil in the tank is decreased to such
extent that the end of the suction pipe
emerges above the oil level in the
tank.
2. Pump case is not filled with hydrau-
lic oil.
3. Strainer of suction pipe is closed, or
clogged.
4. Damage of pump key part(s). Trou-
ble with input shaft and coupling.
1. Pressure is not raised or oil flowrate
does not reach the specified level due
to trouble with other hydraulic equip-
ment than the pump, such as hydrau-
lic motor and various control valves.
2. Large amount of high-pressure oil
leaks due to abrasion of pump sliding
parts.
3. Air is sucked in through suction side
of the pump.
4. Strainer is clogged, or air is sucked
in due to lowering of oil level.
IV-S-14
Hydraulic system
Remedy
Replenish the tank. Raise the oil level
or immerse the end of the pipe in oil.
Fill the pump case with hydraulic oil.
Clean the strainer. Open the suction
pipe.
Disassemble the pump and replace
damaged part(s). Clean all the parts
completely before re-assembling.
Replace, repair or check
hydraulic equipment.
Disassemble the pump. If sliding sur-
faces are roughened, repair them by
re-polishing or lapping. Pay particular
attention to damage to the valve plate.
If damage is irreparable, replace
part(s) and clean all the parts com-
pletely before re-assembling.
Check or replace the suction pipe and
packings, or check tightened parts for
any looseness and re-tighten, if any.
Clean or replace the strainer.
faulty