Fault Finding (cont’d)
Item Symptoms
Related Parts
Trouble
Treatment
Poor
Bending to more than the
•
Replace with new part.
operation
Piston rod
specified limit.
The seal and sliding part material may be
cylinder tube
(Bending distortion:
damaged too, so inspect. If abnormal,
refer to maintenance standards)
renew.
4-1
Tube scored
•
Replace with new part.
Movement
Cylinder tube
As above, inspect the seal and sliding
not smooth
part material.
Abnormal wear, damage of sliding
•
Replace with new part.
Piston rod
area
As above, inspect the seal and sliding
cylinder rod
part material.
sliding part
Foreign matter intruding on piston
•
Remove foreign material.
and cylinder head sliding area
As above, inspect the seal and sliding
part material.
4
Scratches, wear are present
•
Replace with new part.
Piston seal
Inspect the cylinder tube inner surface
also.
Scratches, rust on inside
•
Remove the scratches, rust by honing or
with an oil stone and make the surface
smooth.
Cylinder tube
If the scratch is deep and cannot be
repaired, renew cylinder tube.
•
Renew piston seal.
Piston nut
Loose nut
•
Tighten to specified torque.
Valves
Leak from valve
•
Inspect the valve leakage amount and
service.
Note:
Hydraulic oil expands and contracts due to changes in temperature and pressure. Accordingly, the ram also
expands and this can be mistaken for internal leakage. When inspecting for internal leakage, do so at set conditions.
79 - 4
Section E
Hydraulics
9803/6020
Section E
79 - 4
Issue 1
Hydraulic Rams
4-2
Inner oil
leakage.
Piston rod
extends
when work
stops or
lowers
abnormally
during work.
Also,
specified
operating
speed is not
achieved.
Summary of Contents for JS70
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