i found a used but new condition arm on ebay and began the process of removing my rusted one. Everybody said it was not worth it and i should just get a whole midsection due to the difficulty in removing the old. Well they were almost right. Hung motor from tree (dont knock it, works great), and got motor seperated from mid pretty easy. The hard part was getting the lower large nut off and removing the arm. Cut nut with side grinder and it came off with a little persuasion. The lower gimbal and arm would not seperate. Using a large old screwdriver as a wedge it finally began to move. I wasn't worried about damaging the old arm as new on came it all parts including upper seal and lower nut. Cleaned up tube and put it all back together. About 2 hours total. Waiting on 15 inch prop now to test run and see if RPM's arm up to speed.