C182 DURING A 100 HR CHK WAS FOUND TO HAVE CORROSION AND A CRACK ON THE R MAIN GEAR AXLE FITTING.

Narrative

DURING A 100 HR INSPECTION; NOTICED SOME SURFACE CORROSION ON THE MAIN LNDG GEAR AXLE FITTING WHERE THE ALUMINUM CAST FITTING MATES OVER THE TUBULAR STEEL LNDG GEAR LEG. SCRAPED AWAY BUBBLED PAINT TO SEE IF IT COULD BE CLEANED UP AND TREATED. CONTEMPLATED REMOVING AXLE FITTING TO CHK FOR CORROSION BTWN SURFACES BUT FOUND NO PROC IN MAINT MANUAL AND MOST LIKELY DESTRUCTIVE TO THE CASTING TO DO SO. CLEANED OFF CHIPPED PAINT IN ANOTHER AREA AT THE OPEN END OF THE LNDG GEAR TUBE/CASTING AREA AND DISCOVERED A 1 INCH CRACK EMANATING FROM THAT END UPWARD. AFTER REMOVING THE DAMAGED AXLE FITTING FROM THE GEAR LEG; TWO FIELDS OF CORROSION WERE EVIDENT IN THE CASTING. ONE IN THE AREA OF THE CRACK AND ONE AT THE UNDERSIDE OF THE LNDG GEAR TUBE/CASTING INTERFACE. ASSEMBLY WITH A BARRIER PRODUCT AND APPLICATION OF A FAY SEALANT AT DISSIMILAR METAL SURFACES WOULD AID IN REDUCING INGRESS OF MOISTURE BTWN THESE PARTS WHICH CAUSED THE CORROSION AND SUBSEQUENT CRACKING. ACFT APPROX 10000 HRS OPERATED IN COASTAL ENVIRONMENT.