Cutlass Bearing Replacement - Prop shaft in-situ

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Can anyone give advice on the procedure, assuming that it is possible, to replace a cutlass bearing with the prop shaft still in place. Boat is a 25 foot yacht the with cutlass bearing in the P-bracket. I think I would need to remove the engine to take out the prop shaft, hence the question.
 
In the 'P' bracket if it's brass bodied then I would say it would be impossible. If it is phenolic then it may be possible to drive it out from the front of the bracket towards the back.
Can't see why you would need to remove the engine to disconect the shaft though! How can you remove the engine with the shaft still connected?
 
There was an article with photos just a couple of months ago in one of ybw's magazines (PBO, probably).

You need to manufacture a simple tool: a piece of tube, of the right size to fit around the shaft and small enough to enter the P-bracket, cut in half length-wise, and 2 plates, cut in order to put one in front and one at the back of the P-bracket and with 2 large bolts to push the two plates together.

You put the piece of pipe at the back of the P-bracket, and using the two plates you gently push it inside the p-bracket itself, and it pushes the cutlass bearing out the other way.

It takes some time to build the pieces, but then you do the job in a very gentle way, no hammer needed and no stress on the P-bracket.
 
Gian's solution is identical to that used by a friend of mine about a month or so ago.

It was against my advice, not because it wouldn't work - it did - but because it is almost impossible to avoid damaging the propshaft by deep scratching it this way. And of course, the damage is in the very last place you need it! I tried it this way some years ago on a previous boat and learned the lesson. /forums/images/graemlins/frown.gif

Anyway, he went ahead, and sure enough, there are several long scratches down the shaft in the way of the Cutless bearing. He then considered taking the shaft out to maybe try and 'polish' the scratches out! /forums/images/graemlins/crazy.gif

I don't know whether he did in the end, but FWIW, I'd remove the shaft rather than risk it, with subsequent very high wear that would occur to your new bearing!!

All IMHO of course. /forums/images/graemlins/smile.gif
 
Did my Cutlass bearing this year and I'd say definately not. Getting the old one out is the hard part and the involved a hacksaw blade and a hammer and old screwdriver. The little beasties and calcuim deposits make it hard work and you don't want to score the P bracket.

I had to drop my rudder to get the shaft out of the way and this gave me the chance to clean the shaft completely.
 
Agreed. In the famous words of Mr Punch "That's the way to do it"! But chamfer the inside of the tube and remove sharp corners first to avoid scratching.
 
Many thanks for all the quick responses.

I think I'll have a look at fabricating a tool to push out the bearing and have go. If it doesn't go very smoothly I'll stop and will have to resort to removal of prop shaft. The rudder skeg is too close to allow the shaft to be extracted aft, which is why I'll need to shift the engine.
 
Remember you do not have to remove the shaft - Just get the bit that will be the bearing surface away from the tool. You may well find that you can take off the prop etc and unbolt the propshaft from its coupler and slide it back about four inches. That should give you enough room not to risk the bearing surface.

There is also the trick of wrapping some good string around the flange that some bearings have in the rubber bearing and using swarfega as a lubricant. Tie off the string so it will just swivel round the bearing but not pull off. Then continually rotate the string pulling sternwards at all times and pressing the other end of the bearing with a piece of plastic drain pipe - same internal diameter as the shaft diameter - and eventually it should come out.

An alternative is keep the p bracket stand off part well cooled and blowtorch the bearing housing thus burning out the existing bearing but if you can't keep it cool this will damamge the p bracket mounting which is not a good idea.

The good thing is you should be able to get a small screwdriver in the bearing housing outside of the bearing 'cos the reason you're replacing it is that there's a gap! spray well with WD 40 at each point you push the screwdriver in and this will help the bearing to come out as well.

Fair winds.

PS I just chicken out and get the engineers to do it for about £50 plus the bearing.

Ken
 
I replaced my cutlass bearing this year using a metal tube fractionally smaller than the P bracket, heating up around the bearing with a small blow torch to break the seal and gently tapped it out with a hammer. I then cut it length ways prised it open and removed it. No Probs, no damage.
 
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