Changing shaft seal on Bukh DV10LSME Saildrive

That is great - good luck with your repair 

I would not suggest a small impact driver as the screw goes into heli-coils which is threaded into aluminium. I've taken many of the cap screws out with just an allen key that fits a ratchet and they always come out. Just be sure to clean the paint out from where the allen key fits into first so that so the key fits all the way in.

Edited by Bill Layton - 11 February 2016 at 12:41pm

The small impact drivers are used for 5 and 6 mm screws that are threaded into aluminum. what they really do well is keep the the bit from twisting on the screw head. 

Edited by bal149 - 05 February 2016 at 6:58pm

This is what my sail drive looks like right now.  I thought I was looking at the aft end of the bearing housing, but this looks different than the replacement bearing I have.  Perhaps there is another part covering the bearing housing and the bearing housing will reveal itself when I open the SD....or has someone replaced in the past not using original equipment?  Just trying to get my ducks in a row before I open her up.

Your existing one is the best I have seen for being old. It is likely that the seal is worn. Easiest thing for you to do is to just put your new one in that has a new seal in it. That bit you have costs about $300. On the other hand, if you want to keep the old one, just take it out, chuck it up in a lathe, and deepen the bore at the back by about 1.2mm, then buy two 17x30x5mm seals and stick them in back-to-back and reassemble. The seals will be about $4 each.

The other places water can get in is at the oil drain screw. Typically this has a hard fiber washer that is meant to seat and seal, but with several removals, etc, perhaps it has been replaced with a ss washer or something with no flex and give leading to a leak, or something simple like that. Easy fix. Last place to leak other than the seal is the flange that separates the lower cap on the leg, but there is no reason for that to develop a leak unless it was not assembled correctly by someone along the boat's history.

Otherwise, you leg and seal look great. As Bill said, most have some electrolysis issues at the back end. When the Anode fails, the back portion of that seal and bearing assembly seem to become the new sacrificial anode.

Thanks for the info guys.  I think what I will do is put the new one on, and refurb the old one for next time.  My boat was only in salt water for a total of about 12 months on two separate launches.  I'm sure that helps with corrosion.  The boat started in Lake Erie, then Flathead Lake, then Florida (Salt), then back to fresh water here on the Ohio River.  I'm happy to read that you guys think it looks good.

(on the old bearing housing) That is a circlip that holds in place the flat washer. The flat washer protects the seal. The pic of your new bearing housing shows a different circlip with two holes in it. However that new bearing housing is missing the flat washer. You can use the flat washer from the old one.

No need to be nervous. However please do follow instructions I provided on removing the shaft when you take the bottom off the leg so that you do not lose the correct spacing on the gears. I would say that in keeping your project simple, that is the most important move. The method of re-aligning the gears on the shaft (if you let that assembly fall apart all over the dock) requires procedures that are more easily and accurately done with the entire leg on a work bench. Let's avoid that.

Hi Ron did you happen to take pictures through this process?

Well done! You were lucky to be able to get the seal off. Sometimes they are sort of glued onto the casing they sit into.