TM 5-3895-376-14&P
5-12. PISTON ASSEMBLY MAINTENANCE INSTRUCTIONS - Continued
REPAIR
1.
If piston (4) is reusable, and ring set is to be re-
placed, proceed as follows:
a.
Using a piston ring expander, remove the pis-
ton rings (1, 2, and 3) and discard the rings.
CAUTION
Do not expand rings more than neces-
sary to just clear the outside diameter
of the piston (4). Permanent damage to
the ring may result.
b.
Using the piston ring expander; install the oil
control ring (1) in the lower groove of piston
(4), middle ring (2) in middle groove, and com-
pression ring (3) in top groove.
NOTE
The middle ring (2) installs with the
stepped down shoulder on the bottom
side. Each ring is marked with the letter
"R", which designates the side which must
be toward top of piston.
INSTALLATION
NOTE
If the piston requires replacement, it is rec-
ommended that the rings be replaced
along with the cylinder (Para. 5-11).
1.
If not already installed, install the piston
rings (1,2 and 3), see REPAIR above.
6.
Remove the ring compressor and adjust position
of piston assembly (4) in cylinder so the piston
Set the piston assembly (4) upside down on
2.
pin bore of piston is fully exposed below the cylin-
clean workbench, ensure that the gaps of piston
der (5) liner.
rings are staggered at 120 intervals.
7.
Install the assembled cylinder and piston assem-
Compress the piston rings with a ring compressor.
3.
bly over studs, engaging the top of connecting
rod with piston assembly (4).
Place the cylinder (5) upside down on a clean
4.
workbench.
8.
Install piston pin (6) in piston and connecting rod
bore, tapping with a plastic tipped hammer. Cen-
5.
Position the piston assembly (4) with ring com-
ter the piston pin and secure with replacement
pressor on to the cylinder (5) and push the piston
lock rings (7).
assembly into the cylinder.
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