Shibaura ST330, Workshop Manual

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7. TROUBLESHOOTING (STEERING CONTROL UNIT)
Condition Cause Remedy
Steering wheel too heavy. 1. Steering control unit
(1) Misalignment with column
(2)
Seizure of spool/sleeve ass’y
due to dust entry.
(3) Excessive tightening torque
of 7 end cap bolts (at the time
of disassembly and
reassembly).
2. Pump
(1) Dose not work.
(2) Wear, failure
(3) Improper rating
3. Relief valve
(1) Failure
（
improper operation
）
(2) Too low set pressure
Correct
（
if the steering wheel
becomes lighter by untightening
the bolt tightening the steering
column control unit, the cause is
misalignment with the column.
）
Replace.
Tighten evenly with the specified
torque.
Repair.
Replace.
Reselect pressure and flow rate.
Replace.
Reset.
Steering wheel turns freely. 1. Steering control unit.
(1) Seizure of spool or sleeve
due to dust entry.
Replace.
Cylinder dose not follow up
sufficiently or at all the rotations of
the steering
wheel.
1. Steering control unit.
(1) Air mixed at the time of
installation, replacement
(reassembly), or since unused
for a long time into gerotor.
2.
Cylinder
(1) Air mixed
(2) Broken piston seal
Discharge the air.
Discharge the air.
Replace.
Steering wheel turns reversely
(handle kick). 1. Steering control unit.
(1) Improper valve timing setting
(at the time of disassembly and
reassembly).
2. Tubing
(1) Improper tubing to 4 ports.
Correct.
Correct.
Oil leakage
1.
Shaft (spool, periphery of inner
spline)
2. Joint
(Between housing, spacer plate,
gerotor, and end cap)
Wear of oil seal (X ring)
(1) Contaminated hydraulic oil.
Damaged O-ring
(1) Caught somewhere at the
time of disassembly or
reassembly.
Change the hydraulic oil.
Replace.