This is an obvious sigh of water in the oil. (see photo) The first mistake was not changing the oil in the fall, as is recommended by Sillette. Suspecting broken seals, the skeg was disassembled the hard way. Rather than explain how this was actually done let me say that one should just remove the bolts and break the instant gasket seals with a soft mallet and carefully catch all the parts. I did not have the manual with me but I thought how difficult can this be, second mistake. At this point steel parts were noticed in the bottom of the skeg. Things were getting worse. I realized these were part of the cage for the roller bearings. I had two choices, leave things as they are or find the broken bearing. The sonic drive had been working fine in the fall when the boat was put away. Given this fact and the lateness of the spring the former alternative looked attractive but was not really acceptable. I looked far and near for someone to rebuild the sonic drive. No one had seen this type of thing before and they did not to touch it. It became clear that if I was going to be in the water, I would have to do this myself.
Sillette was called and they were sympathetic helpful and encouraging. They said the sonic drive was designed to be repaired on the quay. Therefore, I ordered new seals, instant gasket and a new boot (I always replace this when I remove the sonic drive from the boat). It turns out I ordered their spare parts kit when I bought the boat and all of these items were in this kit but I forgot to look. They said that if the old seals cut grooves in the propeller shaft then I would need to replace it. Two grooves, one for each seal, were cut into the propeller shaft (see photo). I decided to grind these out myself using a lathe and sand paper. The shaft was polished at the end of this process. It looked very nice. Unfortunately it was a little smaller and would not fit as tight.
The next step was to find the faulty bearing. The top was removed along with the bearing for the spline, which appeared to be OK. This bearing housing was difficult to remove because of the gasket cement. My approach was to remove all of the bolts, warm the surface and tap a thin knife between the two parts. Eventually everything came apart. The top gear was removed using a 6 mm allen wrench and heat (see photo). Locktite is on all of the bolts and bearings. One of the problems was to hold the shaft from turning. This was accomplished using a hose clamp. The screw then provided an opportunity to freeze the shaft. (see photo) Upon removal of this gear the faulty bearing proved to be the top bearing (see photo). The middle joint was broken using the previous strategy, the drive shaft removed and the bearing tapped out using a steel rod. This faulty bearing was replaced and everything reassembled using lots of instant gasket and locktite. Unfortunately, some instant gasket must have gotten on the gears which caused the gears to freeze. There were signs this also happened at Sillette when it was originally assembled so I did not worry too much about it.
The drive was painted again and installed on the boat. This is the third time I have removed the sonic drive so I am getting experienced at this task. I bought some of the synthetic oil, Royal Purple from Rob Hoffman and filled up the leg. By the way, the leg really takes a long time to fill, particularly in the cold spring. To fill the boot the oil must leak through the bearing.
Everything worked fine, better than before. I no longer have a whine at 2200 rpms, a whine present since the boat was purchased. Apparently, complete bearing cages are not essential.
All is still working well after one season. It is much quieter and the oil is perfectly clear. I suspect I will have to replace the seals and probably the propeller in the near future. This will not be very difficult compared to replacing the bearing.
