Removing Shaft from flange on Universal M-25

[rajhnsn]

I've read the posts on this topic and watched the videos posted back in 2011. They recommend separating the two flanges and putting a socket on the shaft, then reconnecting the two flanges and tightening the bolts to create a press. Of course the set screws on the aft flange are removed. I have a couple of questions.

1) Is there a nut on the end of the shaft inside of the aft flange holding the shaft to the flange? I don't think there is but just want to be sure.
2) I have what looks like a 3/4" spacer in between the aft flange and the transmission flange. Is this typical?
3) Has anyone tried to remove the shaft from the flange using a slide hammer connected to the end aft end of the shaft while the flanges are still connected? Does this have the potential to damage the transmission?

I have soaked the flange and shaft with penetrating oil and will heat the flange with a heat gun. I want to remove the flange so that I can replace the stuffing box hose. The packing nut is finally loose after much heat, penetrating oil and very large wrenches.

Thanks for any advice you may have on this topic.

 

[JoeWhite]

I tried hopelessly to remove the flange. Others advised to cut the shaft. After spending over $100.00 on drill bits, grinding stones, and a device to press the shaft out, I ended up cutting it off. I ordered a new shaft and flange.

 

[Stu Jackson]

Has anyone tried to remove the shaft from the flange using a slide hammer connected to the end aft end of the shaft while the flanges are still connected? Does this have the potential to damage the transmission?

Yes. Don't do it.

 

[Ralph Johnstone]

3) Has anyone tried to remove the shaft from the flange using a slide hammer connected to the end aft end of the shaft while the flanges are still connected? Does this have the potential to damage the transmission?

Depending on the force of the blows, yes, this may damage the transmission. Just not worth the risk.

I have soaked the flange and shaft with penetrating oil and will heat the flange with a heat gun.

The whole idea is to heat the flange as quickly as possible and then start pulling AS QUICKLY AS POSSIBLE. If the shaft heats up at the same rate as the flange, they both expand together and nothing is gained.

Given the large mass of the flange hub, an oxy-acetylene torch is recommended. Keep the torch moving all the time and work quickly.

 

[kloudie1]

I don't know what your shaft material is, but most shaft material expands more than the steel flange material so heating, as Ralph says, has to happen very quickly because if flange and shaft get hot together, the fit will tighten instead of loosening.

 

[Charles Erwin]

If the coupler is the split version then the bolts come out, and two steel wedges will do the trick. If not - and the other advice does not work - then the coupler gets cut and there is a particular way to do that. But beware of some things.

(1) The coupler was bored to fit to the shaft with 0 or thereabouts clearance. Over time the internal surface of the bore will develop corrosion;
(2) When the coupler come off the corroded internal bore surface disintegrates, the bore becomes larger, and some debris is probably leftover;
(3) When you put the coupler back on it will not fit quite right.

So you might get away with putting it back on and maybe it goes back square and centered but likely not and that means the replaced old coupler might be slightly cocked - or slightly out of center or both. The point is you will likely setup a vibration when it goes back together.

If the present one needs to get cut to get it off then the new replacement certainly will not fit.

If you want to do this right then I will explain how - but doing this the right way is going to be more work than you think.

Charles

 

[duality]

check out maine sails web site he has a how to

PSS Shaft Seal Installation by Compass Marine How To

pbase.com

 

[Tally Ho]

Here is how I did it….

And I just did it again to separate the coupling off the shaft to install a Volvo dripless shaft seal.

i stead of using the transmission output flange (which on my boat would be very difficult), I use a separate steel plate I had made…

A pain the arse for sure, but you can press them apart with some perseverance.

If you are planning to replace the shaft, it is much faster to cut the shaft and remove it.

Greg

 

[rajhnsn]

Thank you very much everyone for the very helpful input. The information from Compass Marine really helped.

Greg, I've watched your video previously. It was very helpful also. Thank you for putting it up.

I'm going to press it out. I may be able to do press it from the spacer that is in between the flanges. This way I will have less chance of damaging the gear box. I plan to replace the flange but I would rather not take the shaft all the way out. The Compass Marine article talks about getting the flange and shaft "fit and faced". I wonder if I will be able to have the new flange done but not the shaft?

 

[Charles Erwin]

Very good shop in Dennis Mass shows the process here

Fit and Face

Charles

 

[eherlihy]

When I went down this road in 2012
I ended up replacing the old bronze shaft. Because I had everything apart, I had a new cutlass bearing, and new coupling fit & faced. I also decided to get rid of the stuffing box, and installed a PSS Dripless Shaft Seal.

1. There is no nut on either the shaft or the transmission output shaft.
2. I can only guess that the 3/4" spacer is a vibration damper / flexible coupling.
3. DO NOT USE A SLIDE HAMMER! If you heat the coupling with a heat gun, using a socket as a spacer while you tighten the flange bolts will push the coupling off the shaft. Once you get the coupling moving, the coupling should slide off the end of the shaft.

Here is a pic of what the shaft, coupling and PSS shaft seal looked like after I installed them;

 

[Tally Ho]

Thank you very much everyone for the very helpful input. The information from Compass Marine really helped.

Greg, I've watched your video previously. It was very helpful also. Thank you for putting it up.

I'm going to press it out. I may be able to do press it from the spacer that is in between the flanges. This way I will have less chance of damaging the gear box. I plan to replace the flange but I would rather not take the shaft all the way out. The Compass Marine article talks about getting the flange and shaft "fit and faced". I wonder if I will be able to have the new flange done but not the shaft?

If the shaft is the original bronze one, inspect it carefully for cracks. I went through this with mine, and in the end, scrapped the shaft for a new SS one as the bronze one had cracks, and some pretty deep wear areas.

I don’t think you can fit and face a new coupling to an old shaft…I think they have to be done together at the shop.

You may be best served with a split coupling, if you are using your old shaft. if I were to do it again, I think I would use a split coupling (if you plan to replace your dripless every so often as recommended, it makes getting the coupling off and back on much easier). i pressed mine apart recently to install a dripless seal, and could after a few years things were starting to ”bond” together enough I had to press them apart. Not nearly as hard as the first time, but still scraped my knuckles a bit.

Greg

 

[rajhnsn]

The shaft is stainless so I guess that a PO has replaced it in the past. I can't get the shaft out of the boat at this time because I will not be able to get the rudder off without lifting the boat. Not sure an extra lift is in the budget at this time. The boat is on McAdam and I'm sure the yard will not let me dig a hole to drop the rudder. The cutlass baring is in good shape so I don't need to do replace it at this time. In watching Greg's video, he was able to get the shaft passed the rudder by pressing out the cutlass baring. If I don't have to do this, I'd like to avoid it.

On another note, those of you that installed the PSS shaft seal, did you add a new through hull?

Thanks again for all the information. It is really making a difference in my plan of attack.. BTW does anyone want to buy a slide hammer?

 

[Charles Erwin]

So why not just repack the stern gland with flax (PTE) and skip the PSS altogether. Ralph (at #4 above) is a good source on this tactic.

Remember if you do get the PSS in place successfully - you will need to go through the same thing again in 6 years time.

In short - whole lot of project for precious little gain.

Charles

ps - PSS does not need any (separate) through hull/sea cock.

 

[Tally Ho]

If the shaft is SS, then it sounds like was replaced. I would work on pressing off the coupling. It took me a few days. If the spacer thing is metal, you might be able to use it instead of the transmission flange. It takes time and patience, constant resetting of the bolts and the socket…since your shaft has been replaced, maybe it wont be so bad.

This winter, I pulled the coupling back off, removed the stuffing box, inspected the shaft for wear, and then bought and installed a Volvo Penta dripless shaft seal. Simple, clean design. I hope it works well.

Big difference in the size of the old stuffing box, and the new Volvo…


Looks good once installed…


I was able to push my coupling back on…with a little help from a hammer. I tried to put some lanacote on the shaft before pushing them back together…hope it makes removal in the future easier. If not, I will try a split couplin.

Good luck.

Greg

 

[rajhnsn]

So why not just repack the stern gland with flax (PTE) and skip the PSS altogether. Ralph (at #4 above) is a good source on this tactic.

Remember if you do get the PSS in place successfully - you will need to go through the same thing again in 6 years time.

In short - whole lot of project for precious little gain.

Charles

ps - PSS does not need any (separate) through hull/sea cock.

I have considered doing this but it seems like a good idea to replace the hose. It seems like this job is taking me down a rabbit hole.

 

[eherlihy]

Remember if you do get the PSS in place successfully - you will need to go through the same thing again in 6 years time.

In short - whole lot of project for precious little gain.

I have had a PSS installed in my O'day 35 since 2012, and I disagree with both of these points.
While the manufacturer states that shaft bellows need to be replaced every 7 years, I have heard of them going for far longer. I, however, replaced the bellows shown above in 2019, after 7 years of use. I did not need to remove the shaft, only the coupling. Doing this replacement only took an afternoon, because the coupling and shaft had not been constantly sprayed with seawater, and by using the technique that I describe in the prior post it came off easily.

Having a dry bilge is a good thing.

 

[RoyS]

Suggest using elastic nuts on the four coupling bolts. They may be metric size BTW. Paint all when done.

 

[Charles Erwin]

I have had a PSS installed in my O'day 35 since 2012, and I disagree with both of these points. I did not need to remove the shaft, only the coupling. Doing this replacement only took an afternoon, because the coupling and shaft had not been constantly sprayed with seawater, and by using the technique that I describe in the prior post it came off easily. Having a dry bilge is a good thing.

Disagreement is healthy. But PSS is not for everyone. You are fortunate indeed to have had such success in your r/r the bellows and maintain coupler centricity - not everyone has had such good fortune. I think we are entitled to consider all the factors and not get fixated on one benefit alone.

To the point here however this is a first install. The PSS unit is plenty expensive to start with. There is just a lot of work and expense involved. Comparing cost to benefit is a useful exercise. Traditional stuffing boxes with modern packing like Duramax carefully maintained do not leak at rest and your shaft is at rest the lions share of the time. I bring more in on my boots on a rainy day than the very few drips a minute the shaft produces when running.

One other point. Consider a stop collar on your shaft - just in case.

Best wishes for a good New Year to everyone.

Charles

 

[rajhnsn]

Much to think about. I'm going to the boat on Friday to take a first crack (hopefully not literally) at the flange removal by pressing it off. If I don't get any movement after the first few terns on the bolts, then I'll add more penetrating oil and save it for another day. I'll let you all know how I make out. This has been very educational for me and I'm very grateful for your ideas and input.

I'll search a stop collar to find out more about it.