jcb JS300 Service Manual page 906

Item Symptoms Related Parts
Back up ring
Wiper ring
Piston rod
1 sliding part oil
leakage
Cylinder head
Back up ring
Oil leakage
2 from cylinder
head joint
Cylinder head
Cylinder tube
E-245
Trouble
The protrusion of the heel of the
packing is excessive.
Foreign matter is biting into the
lip. The lip is damaged.
There are also other abnormal
damage.
Wear is large and the clearance
with piston rod exceeds the
*maximum permissible value.
(*Refer to maintenance
Bushing
standards for maximum
permissible value.)
Large scratch on the sliding part. Replace. Also inspect the piston rod.
Scratches, rust on the seal
attachment parts.
Foreign matter biting on inner
and outer diameter.
O-ring damaged.
O-ring
Deformation, protrusion
Looseness
Bolt Looseness, stretching, broken
Abnormal bulge
Hydraulic System Fault Finding
As a rule, replace the rod packing at the same
time. (It is desirable to replace parts which are
attached to the buffer ring at the same time). It
is possible that abnormal high pressure is the
cause. Check the same as above (heel of
packing protruding).
Remove the foreign matter.
Replace.
Replace.
Remove scratch, rust with oil stone. If it cannot
be repaired, replace the cylinder head.
Remove foreign matter
Replace 'O'-ring if damaged.
Inspect inside tube: if any scratches or
rust, make surface smooth with oil stone
Inspect cylinder head 'O'-ring groove: if
any scratches or rust, make surface
smooth with oil stone.
Inspect back up ring: if any deformation or
protrusion, replace.
Confirm the above and replace 'O'-ring.
Replace with 'O'-ring.
Disassemble cylinder head and inspect
'O'-ring and back up ring.
Check tube and cylinder head thread for
damage. If any damage, replace.
After inspection, tighten to specified
torque.
Replace all bolts and tighten to specified
torque.
Replace with new parts. Oil leakage from
connecting parts may be caused by abnormal
pressure (including cushion pressure). Inspect
the tube for bulges, deformation and check the
circuit pressure.
9813/5100-1
Section E - Hydraulics
Hydraulic Rams
Treatment
E-245