Komatsu Galeo PC138US-8 Shop Manual page 891

50 Disassembly and assembly
2. Sub-assembly of piston assembly
1) Expand piston ring (13) using tool (U5).
a Set the piston ring on tool (U5) and
expand it by rotating the handle eight
to ten times.
2) Reduce piston ring (13) using tool (U6).
3) Mount the backup ring and O-ring (14).
4) Engage wear ring (12).
5) Engage ring (11).
a Be careful not to expand the ring
abutment joint too much.
2
Ring groove: Grease (G2-LI)
3. Piston rod assembly
1) Set piston rod assembly (2) on tool (U1).
PC138US, USLC-8
2) Assemble head assembly (7).
3) Fit O-ring and backup ring to collar (6),
and assemble.
Arm cylinder and boom cylinder.
q
4) Assemble plunger (5).
Arm cylinder and boom cylinder.
q
a Check that there is a small amount of
play at the tip of the plunger.
5) Set cushion plunger (10) on the piston rod
and engage 11 balls (9) and fix them using
cap (8).
For the arm cylinder only.
q
6) Assemble piston assembly (4) in the fol-
lowing procedure.
When the rod and piston assembly
q
(2) are reused
a Completely wash them and clear
them of cut powder or dust.
1] Screw piston assembly (4) and
tighten it using tool U2 until the
screw hole position completely
fits.
a Eliminate screw burrs using
a file or the like.
2] Tighten screw (3).
2
Screw (3): LOCTITE No. 262
3
Screw (3) :
Boom, arm and blade :
Bucket: 30.9 ± 3.4 Nm
SEN02713-00
66.2 ± 7.35 Nm
{6.75 ± 0.75 kgm}
{3.15 ± 0.35 kgm}
35