Shibaura ST330, Workshop Manual

Page: 192 / 250

182
7. Troubleshooting
Condition Cause Remedy
1.
When the control lever is set at
the lifting position, the
implement does not raise.
(1)
The implement is heavy.
(2) The oil pump discharges no oil.
(3) Dropped relief set pressure.
(4) Shut-off spool is not closed.
(1)
Check the implement.
(2) Replace the oil pump.
(3) Adjust the set pressure.
(4) Check the spool for dust and
scarring.
2.
When the control lever is set at
the neutral, the implement
lowers at high speed. (Hunting
is repeated.)
(1)
Worn out housing and spool.
(2) Leak in the cylinder.
(3)
Scar on the check valve seat
surface.
(4) Leak from lowering valve.
(1)
Replace the valve ass'y.
(2)-1 Replace the O-ring.
(2)-2 Replace the liner and piston.
(3) Replace the valve and bush.
(4)
Replace the lowering valve
ass’y.
3.
Implement rises more slowly
than specified.
(1)
Improper sliding of shut-off
spool.
(2) Leak in the cylinder.
(3)
Reduced oil pump volumetric
efficiency.
(4) Clogged oil filter.
(5)
Hydraulic oil.
(1)
Correct or replace.
(2)
Inspect or replace the O-ring,
liner and piston.
(3) Replace the pump (in case of oil
leak).
(4) Replace the filter (check oil for
contamination).
(5) Use proper hydraulic oil
(SAE80 or ISO VG46)
4. Rapid rise of oil temperature.
(1)
Seizure of oil pump.
(2)
Reduced volumetric efficiency of
oil pump.
(3) Use with the relief valve working.
(1)
Replace the pump (check the oil
for contamination).
(2) Replace the pump (check the oil
for contamination).
(3)-1 Check the changeover valve
position.
(3)-2 Dislocated feedback link.
5. Noise generated.
(1)
Seizure of pump.
(2) Insufficient suction of pump.
(3) Air sucked.
(4)
Hydraulic oil.
(1)
Replace the pump.
(2) Replace the oil filter.
(3)-1 Check or replace the O-ring of
suction pipe, filter or other
positions subjected to seizure.
(3)-2 Check the suction pipe for air
sucked.
(3)-3 Check the oil pump oil seal for
air sucked.
(4) Use proper hydraulic oil
(SAE80 or ISO VG46).
6.
When the implement is held at
a certain position and the
engine is stopped, the
implement lowers naturally too
fast.
Take the same measures as for above 2.