Help - shaft nut threaded, how to change bearing now?

[pandw]

So my boat (Beneteau Oceanis 50) is on the hard, and we are having the shaft bearing and stern gland replaced.

The boat is too close to the concrete hard to remove the rudder, so we decided to remove the gearbox and slide the shaft forwards.

However, when trying to remove the nut on the shaft coupling flange, it was discovered that the nut was threaded. It will do up, but will not back right off.

Any good ideas how to get this nut off, without wrecking the shaft?

I'm trying to avoid pulling the engine out into the saloon, and pulling the whole shaft forwards.

Any help or ideas would be greatly accepted.

[Jammer]

I would recommend the use of excessive force, ideally applied by a large impact wrench so that you don't have to block the prop.


The shaft will probably be fine, if not, clean up the threads with a die. Use a new nut when assembling.

[coopec43]

I don't disagree with anything Jammer has said but the nut is obviously stuffed so I'd cut it diagonally without hitting the shaft. Then I'd use a cold chisel to spread (expand) the nut so that it can be removed.

Is it possible to use a gear puller to apply force as you unscrew the nut?

(Of course you are turning the nut the right way!!!)


NOTE: I've re-read your post and I'm not sure I understand the problem.

[rbk]

Reverse threaded? Also be careful smashing the coupler. It’s suprisingly easy to knock them out of square to the shaft. Good idea to get it faced and fitted by a machine shop before it goes back in. You’d usually get a new coupler but yours looks pretty good.

[coopec43]

help-how to remove prop frozen nut ???

https://forums.sailboatowners.com/in...en-nut.128639/

[coopec43]

Maybe some clues here?

https://www.youtube.com/watch?v=zQiHTf_TyNE

https://www.youtube.com/watch?v=ZEnGmLv9B1Q

[Rickalexander]

Originally Posted by pandw

So my boat (Beneteau Oceanis 50) is on the hard, and we are having the shaft bearing and stern gland replaced.

The boat is too close to the concrete hard to remove the rudder, so we decided to remove the gearbox and slide the shaft forwards.

However, when trying to remove the nut on the shaft coupling flange, it was discovered that the nut was threaded. It will do up, but will not back right off.

Any good ideas how to get this nut off, without wrecking the shaft?

I'm trying to avoid pulling the engine out into the saloon, and pulling the whole shaft forwards.

Any help or ideas would be greatly accepted.

Hi your not getting any advantage taking it off if your sliding shaft fwd into gearbox area. Remembering the nut is on the shaft that is the end of the shaft. Photos only show gearbox in the way of shaft going fwd is this true. If it is take out gearbox only leave connector on the shaft. Kind regards Rick

[Uncle Bob]

Originally Posted by Rickalexander

Hi your not getting any advantage taking it off if your sliding shaft fwd into gearbox area. Remembering the nut is on the shaft that is the end of the shaft. Photos only show gearbox in the way of shaft going fwd is this true. If it is take out gearbox only leave connector on the shaft. Kind regards Rick

Ditto, I can't for the life of me see why you want to remove the coupling, remove the gearbox to allow the shaft to slide far enough forward to do the bearing.

[skipperpete]

Originally Posted by Uncle Bob

Ditto, I can't for the life of me see why you want to remove the coupling, remove the gearbox to allow the shaft to slide far enough forward to do the bearing.

The OP originally said he also wanted to change the stern gland.

[Suijin]

Originally Posted by Uncle Bob

Ditto, I can't for the life of me see why you want to remove the coupling, remove the gearbox to allow the shaft to slide far enough forward to do the bearing.

Can’t get the stuffing box off without removing the nut. He does not want to pull the whole shaft (assuming he has a puller for the cutless and it’s in a skeg) just get the old gland parts off.

[Jammer]

Originally Posted by rbk

Reverse threaded?

Good point. Always something to watch for with fasteners that "loosen" only a little and then seem to get stuck.

[Ivanvet]

Hey,

We were on a similar situation last summer on our Beneteau 473. In our case we needed to replace the old shaft seal. When trying to use a puller to pull (duh) the coupling, we didn't know there was a nut at the end. We kept pulling, and pulling, and using more brutal force until I decided to take a picture like the one you took so I could see the (destroyed by then) nut. We removed the nut without problems but then I was left with ****ed up threads on the shaft. I spent nearly 4 hours with a small file re-threading the shaft and then we used a die. It was great at the end. This story probably doesn't help you, but as a piece of advice... just be careful with brutal force if the nut is still in place.

Also, assuming that your B50 is the same design as the B473, the nut is not reversed threaded. If your shaft is 30mm (like ours), the nut is an M16 coarse thread nylock nut. I would suggest ordering a couple of these in advance because it took a few trips and days to different chandleries to get one.

As in how to remove the stuck nut? I didn't come across that problem so I'm not sure I can help. We used a ton of PB blaster days prior to having to pull everything and by the time we had to remove it was easy.

Good luck,

Ivan

[Ivanvet]

This picture shows the moment of... oh crap that's why it doesn't come out.

[nhschneider]

When I went to replace the cutlass bearing on my Contest 48 (fin keel, skeg-mounted rudder), I wound up having to pull the engine because the prop shaft would hit the skeg (no strut). It took me about three days to complete the project.

Fair winds and calm seas.

[wrwakefield]

I don't know about getting the nut out of the inside of the coupling unless you can get an impact wrench on it... [I find a compact air or electric impact wrench (not impact driver...) useful for such cases...]

RE: Replacing your cutless bearing— with shaft in place:

If your cutless bearing is in a strut— and if you cannot conveniently remove the shaft from the cutless to replace the bearing [as was my case]— take a look at the successful approach I used to replace the cutless with the shaft in place [using a specialized tool from StrutPro.]



My efforts are documented [with annotated photos] in this blog post for anyone interested in more details.

Good luck!

Cheers! Bill