79 - 1
Section E
Hydraulics
9803/6020
Section E
79 - 1
Issue 1
Hydraulic Rams
Fault Finding
The chart below lists some possible problems and suggested remedies. The types of problems fall into four main categories as
follows:
Item
Symptoms
1
Oil leakage from piston rod sliding part.
2
Oil leakage from cylinder head joint.
3
Oil leakage from pipe and cylinder tube welds.
4
Faulty operation
Item Symptoms
Related Parts
Trouble
Treatment
On the sliding surface, there are
1
Use an oil stone and remove the scratch
scratches and rust that can be
and make the sliding surface smooth.
felt by the fingernail.
If oil leakage continues even though the
rod surface is made smooth, the scratch
may have
damaged the U-ring and
other
seals, so dismantle and
inspect.
Piston rod
2
If the scratches and rust cover such a
wide area that they cannot be repaired
by an oil stone, renew the piston rod
and U-ring, wiper ring and seals and the
piston rod bearing member.
Piston rod
The plating is peeling.
Re-plate or renew the piston rod.
1
sliding part
Also inspect the seal and piston rod
oil leakage
bearing member and renew if damaged.
Foreign matter is biting into the
Remove foreign matter.
inner and outer surfaces of
If there is damage to packing, renew it.
the packing.
Rod packing
There is a scratch on the inner
Renew.
(Buffer ring
surface.
U-ring)
Possibly due to burning caused by
The lip and groove parts are
adiabatic compression from air remaining
locally carbonized (burned).
inside the ram. After renewing the
packing, first operate the ram at
low-pressure, low speed to sufficiently
bleed the air.
Summary of Contents for JS70
Page 65: ......
Page 99: ......
Page 189: ...Section E Section E Hydraulics 9803 6020 Issue 1 33 4 33 4 Control Valves Control Valve 291360...
