Drive Shaft Wobble

[RWP]

Sorry if this has been covered before, but I coulnd't find anything defnitive in a search...

Mine is a 1998 28TE that was repowered three years ago with a new Yanmar 315. Just discovered a few weeks ago that there has been sufficient salt water intrusion to cause corrosion on the engine exterior. Turns out sea water has been virtually flooding in around the wobbling drive shaft at crusing speed, flinging salt water all over. The shaft was reconditioned and engine/shaft realigned to within about 6/1000th. Back on water, the shaft still wobbled badly and water gushed in. The mechanic now thinks the solution may be to replace the dripless shaft seal with the old fashioned packing gland. Is this a common problem and solution? Just makes me sick to have nearly ruined that new engine...

[Russell]

I had this same problem after my engine was pulled and replaced for transmission work. The wobbling made the new dripless shaft seal leak like crazy. Turned out the stern bearing housing was broken. The tube part broke from the outer part and the two bolts are not adequate to keep the shaft under control without the tube inserted into the skeg. I think they let the weight of the shaft snap the housing at some point of the installation/removal but they showed me how pink the metal was from electrolysis. This housing is not bonded and the rubber seal keeps it from electrical contact with the shaft zinc. You can get a replacement bearing housing from Buck Algonquin. http://www.buckalgonquin.com/pages/Prod ... _page.html
My mechanic did not know where to get one so he solved the problem by buying a longer shaft bearing and let the extra length act as the tube. Wobbling of the shaft cannot be caused by the dripless shaft seal and I would not go back to the old stuffing box.

[RobS]

Are you looking to replace the drip-less shaft seal in order to correct the water leak or to correct the wobble. How confident are you with the engine alignment? Have you checked the engine mounts? Are they tight, is the rubber structurally sound, etc.. The wobble may have damaged the shaft seal or the boot that connects the seal carrier to the shaft log.

[Russell]

I forgot to mention that the wobbling damaged the Tides shaft seal and that was replaced at the same time the stern tube was repaired.

[RWP]

My understanding of all this is incomplete at best, but here is the most accurate a represenation I can make of what my mechanic has reported, after doing considerable research on the issue:

As it came from the factory, the boat likely had a shaft of a certain metric diameter, very close to 3/4 inch. Somewhere along the line, that shaft was replaced with one that is 1/2 inch. The shaft should be supported with a strut and cutlass bearing every certain number of inches -- and mine is over that specification by some considerable amount. The best cure for the wobbling shaft would be to add a support. However, a far less costly...yet satisfactory fix according to his sources (which may include people in this group)...is to put in an old fashioned stuffing box, which provides more support/rigidity than the dripless version.

Yes, I am confident about the alignment and motor mounts. That's what the mechanic worked on last week before we took the boat out and found the wobbling still wasn't fixed.

What confuses the dickens out of me is that I know that many Albin 28s are powered with the Yanmar 315 engine...and I have never seen any comments about drive shaft wobble being a common problem. I read tons of posts on this site before I bought the boat and did the repower. You don't feel much vibration at all at the helm, but you can see that shaft jumping around like mad when you watch it at crusing speed, and like I said earlier, water pretty much pours in around the dripless seal.

[RobS]

I have no knowledge of a 28TE with anything other than a shaft dia of 1-1/2". It cannot be 1/2", you may have misunderstood him? How about the cutlass bearing or the stern bearing housing? Has that been checked, could it be cracked, loose, broken/sheared off bolts??

[RWP]

Oh for dumb! Of course it is 1.5 inches. Yes, the cutlass bearing is fine and I think he is going to double check the rear support. At this point I think replacing the drip less seal is what we'll try. He is confident that will work -- the ultimate objective being to stop the salt water from coming in through the shaft opening and spraying all over. I discovered the problem when the starter motor became so corroded it quit working. Good grief.

[efishnsea]

I hate to chime in on this but I cant and dont believe a stuffing box will rectify a wobbling shaft. The stuffing box is purely a stop leak device and has no bearing properties. Rob stated that the cutlass bearing should be checked and it behooves you to pehaps have a second opinion before you have a more catastrophic failure. Either the shaft is bent or the cutlass bearing is not bedded in proper or the engine is not alligned correctly. Have another professional oppinion. Bob

[jleonard]

And alignment of .006" is not that good really. Not the root cause of your problem, but just sayin'.

[RobS]

True. These boats have a 5" coupler. The rule of thumb is no more than a 1/1000 out per inch of diameter so you are just outside of that. The target is to get it right on and .003" is a better figure to shoot for.

[jleonard]

I forgot to mention that the wobbling damaged the Tides shaft seal and that was replaced at the same time the stern tube was repaired.

If you are going to replace the Tides seal because the wobbling shaft damaged it, and you do nothing else, all you will accpomplish will be to install another seal that will get damaged.
The Tides seal comes with a very flexible silicone hose that "locates" the seal and allows it to float with the shaft. (I installed one in my boat). This should be flexible enough to allow for some shaft runout...and all shafts have some runout, some you notice, some you don't.
If your mechanic is convinced that the wobble caused the failure, then you should install a longer silicone hose to give the seal more room to move with the shaft. That is the design intent of the tides seal system.

[Capeandisland]

Please excuse my intrusion into your thread, i am a huge fan of this site and obviously of Albin's. however i couldnt help but notice a few issues that i felt compeled to comment on...

RWP, if your mechanic is recommending a change in shaft seal, whether to a stuffing box or not, as a potential cure for shaft instability or alignment, you should strongly consider seeking a second opinion. likewise, if you are experiencing shaft vibration to that extreme, the integrity of your cutlass bearing has been jeopardized and should be replaced.

[RobS]

Please excuse my intrusion into your thread, i am a huge fan of this site and obviously of Albin's. however i couldnt help but notice a few issues that i felt compeled to comment on...

This is the basis of putting problems/issues on the board, for constructive feedback from others to aid in troubleshooting and correcting.

[Capeandisland]

Thanks, As it was my first post, I wanted to make sure i was being polite.

[RWP]

At this point, it looks like the issue is resolved. The mechanic did indeed replace the dripless seal with an old fashioned stuffing box and cutlass bearing. On a sea trial, no water came in through the shaft, and the shaft vibration was all but gone. I'm going to take it slow and easy with this new system for a while...see how it does on short trips before going very far from home port...but at the moment, it's looking good.

Thanks to all for their comments and kind wishes.