V. Servicing
B) Piston sliding surface Repair seizing mark and/or scratch area with pneumatic grinder stone, oilstone and/or emery paper. NOTE! Using breaker with unrepaired condition will eventually destroy cylinder. Repair at early failure stage before too late. NOTE! Polish to perpendicular direction only. If not, circularity will be spoiled. NOTE!
Wash repaired piston before reassemble.
Caution on using pneumatic grinder stone, oilstone and/or emery paper Fault type
Condition
Remedy
Vertical scratch
Striped scratches to the direction of piston striking.
Remove burrs by polishing to the circumferential direction.
Repair at early stage as scratches may develop to a fatal failure.
Remove burrs sticking out of grooves and finish edges.
Scratch in the grooves
Vertical scratch or rust pit on lower part of piston
Chipped corner of sliding section
Remove burrs by polishing machine to the circumferential direction. NO polishing more than 0.05 mm in depth from normal diameter. Replace the piston if scratches and rust pits are not removed by that much polishing.
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