What was found
DURING THE 6 YEAR/8,000 CYCLE INSPECTION OF THE MAIN LANDING GEAR ASSEMBLY (101-810082-3), THE INTERNAL DIAMETER OF THE PISTON (101-810213-0001) FROM THE PISTON/AXLE ASSEMBLY (101-810045-0009) HAD MAJOR CORROSION BELOW THE LOWER SEALING PLUG. THIS CORROSION WAS CAUSED FROM MOISTURE TRAPPED UNDER THE LOWER SEALING PLUG (101-810047-1) AT ASSEMBLY AND NO PROTECTIVE COATING APPLIED TO THE METAL BEFORE INSTALLATION OF THE PLUG. THIS PISTON IS NOW BEYOND REPAIR AND VERY EXPENSIVE TO REPLACE. RECOMMEND THE USE OF PRESERVATION OIL UNDER THE LOWER SEALING PLUG AT THE SCHEDULED 6 YEAR/8,000 CYCLE INSPECTION DURING ASSEMBLY TO DISPLACE ANY MOISTURE AND PROTECT THE BARE METAL ALONG WITH SEALING THE PISTON THROUGH BOLT.