PYI Shaft Seal

PYI (PSS) Shaft Seal Leaking

My dripless shaft seal is leaking when underway. (It's fine when not in gear or engine off.) Not alot but just enough to fling water spray in the ER. I went to a yard and ask how much to pull the boat and replace the seal. (Kit?) The manager said to just burp the bellows, allowing the inrush of water to flush out the sealing surface, polish the two surfaces with 600 paper, then loosen the 4 set screws on the SS collar and increase the load on the coil spring. (About an inch)

Has anyone done this? The seal is 9 years old and maybe due for a complete replacement.

Any advice is welcome other than "don't put the boat in gear."

Sounds like the yard manager knows what to do, but at 9 years a replacement kit of the bellows would not hurt. I just bought a kit from PYI, great service, fast delivery and reasonable pricing.

Walt:

I just replaced our bellows this spring as it was coming up on the 12 year mark and the company recommends replacing every 10 years.

Not a very difficult job and only a little blood was shed. The company does warn that new set screws are to be used if the originals are loosened. Instructions with the bellows replacement kit tell you how to pre-load the bellows depending on the shaft diameter. There is no "coil spring" of which I am aware.

Mine is 8 yrs old and have always "burped" it from time to time approx 3 times a year.

Anybody know of a bellows failure? I'm sure there are many of these seals out there w bellows adjusted for the wrong pressure on the bearing. This is not my first PYI seal and the only problem I've ever had is the sleeve bearing half coming loose, moving fwd and letting large amount of water in while underway.

Met the owner of the company once and it was a very bad experience but the products are good.

manyboats said:

I'm sure there are many of these seals out there w bellows adjusted for the wrong pressure on the bearing. This is not my first PYI seal and the only problem I've ever had is the sleeve bearing half coming loose, moving fwd and letting large amount of water in while underway. .

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I'm crawling into the ER tomorrow to check those two possibilities out.
Makes sense...thanks, Eric.

manyboats said:

Mine is 8 yrs old and have always "burped" it from time to time approx 3 times a year.

.... the only problem I've ever had is the sleeve bearing half coming loose, moving fwd and letting large amount of water in while underway.

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If your PYI seal/bellows arrangement has a coolant water hose connected to it, I am not sure "burping" is necessary. If it has no such hose, then I think that you are supposed to burp upon launch.

If you put a hose clamp on the shaft just forward of, and touching, the bearing, that should prevent it moving.

Also, the bellows should be pre-loaded the correct amount for the diameter of the shaft. PYI website and the bellows kit have the instructions on this.

Watler "crawling" ....

Is that going to be a photographed event?

manyboats said:

Walter "crawling" ....

Is that going to be a photographed event?

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Yes, but just partially.
It's interesting to me where the apparent leak is. I say apparent as when I powered up the boat I didn't notice any leak at either idle or in gear at idle.

The photo is at idle and in gear.

Another option for those who are considering installing a dripless shaft seal is Tides Marine, shaft seals. You are able to put an extra seal on the shaft which allows you to change out the seal if it starts to leak while in the water.
Just another option

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SeaHorse II said:

Yes, but just partially.
It's interesting to me where the apparent leak is. I say apparent as when I powered up the boat I didn't notice any leak at either idle or in gear at idle.

The photo is at idle and in gear.

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Apparently someone has been too busy boating to polish his only prop shaft log housing. Last time I saw that much green I was in Ireland.

Maybe Mark has a picture of a proper-looking shaft log. (I sure don't! )

FlyWright said:

Apparently someone has been too busy boating to polish his only prop shaft log housing. Last time I saw that much green I was in Ireland.

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People who actually polish their shaft logs really need to fill their day with other pursuits . (In other words, "Get A Life!) Those that point this condition out might be better served with making sure their contaminants stay on the outside of their fuel tanks.

I replaced our PSS seal at 7 years but with hindsight there was no reason to do so. The unit was fine. It is easy to see any deterioration of the bellows (cracking, drying) and there was none. The seal itself still has life in it provided you can still move it to tighten the face seal spacing. Loosen the seal (release the grub screws) and slide it apart slightly. Clean the face seals with acetone to get rid of oil/grease, then polish with fine grade wet/dry sandpaper. Retighten the seal. You can re-use the grub screws but should reverse them so that the exterior screws are now the inner screws. also make sure you have a shaft zinc or similar (large hose clamp) on the inboard side of the seal unit to prevent any chance of the unit slipping open along the shaft. We had a persistent fine spray until I did this procedure. Dry now!!

Chrisjs said:

We had a persistent fine spray until I did this procedure. Dry now!!

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I am amazed at the number of folks who have had similar problems with their PSS shaft seals. This doesn't bode well for the longevity of these seals. The old style shaft logs are looking better & better!

I would not say this represents a "problem". Just routine maintenance similar to having to tighten a shaft log.

SeaHorse II said:

People who actually polish their shaft logs really need to fill their day with other pursuits . (In other words, "Get A Life!) Those that point this condition out might be better served with making sure their contaminants stay on the outside of their fuel tanks.

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Chrisjs said:

I would not say this represents a "problem". Just routine maintenance similar to having to tighten a shaft log.

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I had a similar PSS seal problem, small drip while under way. "Burped" the rubber housing, cleaned the mating surface with a cotton cloth and added the correct pre-load to the system. Issue solved!

IMHO there is no mechanical system that does not need a little TLC. Either pay attention to it now and repair or later. The choice is yours. The boat $$$$ is keep adding up if maintenance is deferred.

dwhatty said:

If your PYI seal/bellows arrangement has a coolant water hose connected to it, I am not sure "burping" is necessary. If it has no such hose, then I think that you are supposed to burp upon launch.

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I couldn't find any mention of the water connection negating the burping but it does make sense.

knuckelbuster said:

....and added the correct pre-load to the system. Issue solved!

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By correct pre-load, do you mean you increased the pre-load or loosened the collar and re-compressed the bellow per the book?

I've had several recommendations saying that it is not necessary to haul the boat for the cleaning of the bellow and resetting the pre-load. When I burp my seal, water really gushes in and I can't imagine having enough time to accomplish these cleaning suggestions (wiping the seal face, sanding, etc.) without the bilge pumps joining the procedure.

I personally would not try to polish the face of the seals. One of the sealing surface is steel (tungsten, 312 or 304 SS) the other is a carbide. Both have been polished/trued to seal. IMHO any 'polishing 'could impede the sealing properties.

Yes there will be water 'gushing' in as you separate the coupling but this can wash any contaminants out of the rubber housing. Clean the mating surfaces then slide the coupling back together, when the water stop flowing in, mark the shaft on the movable coller side. Check your spec for the amount of pre-load, mine was 1 1/2". Push the coupling together and tighten the set screws.

I hope your TLC on the PYI seal goes well.

While I was down below and at the dock with nothing running . I bumped the bellows and water started to come in . Then just moved it back and it stopped . I'm new these and that just seemed to easy for water to start coming in and just to slightly move it and the water stopped . This can't be normal can it . Does it need more tension ?

Sounds normal, Pack Mule. I had the same thing happen to mine when I nudged it. Scared the bejebes out of me at the time. I've tried not to do it ever since.

Pack Mule said:

I bumped the bellows and water started to come in . Then just moved it back and it stopped . This can't be normal can it . Does it need more tension ?

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It's normal on my boat and I think it needs more compression on the bello but I can't confirm that with anyone in the know. Stay tuned!

manyboats said:

Met the owner of the company once and it was a very bad experience but the products are good.

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There is a story there that I am sure I'm not alone in wanting to hear. Can you elaborate?

PackMule, Although there is a rush of water when you bumped the rubber, it is a testament to their sealing ability that the water stopped when they re-aligned. Enclosed is the PYI's description for installation and maintenance for their PSS seal. The site is well done and has a video for installation.

I can not comment on the need to add more pre-load because I do not know that number as it now. If is were me, I would slide the coller back until the seal starts to leak and add the pre-load that the spec call for. that

PSS Shaft Seal: The world’s leading dripless seal.
My experience with these type 1 seal was from processing equipment. From my experience, seal of this type can overcome some misalignment (<.030) and contamination(< 5% TDS) of the liquid in the sealing area. Perfect for the boating environment.

This seal in question has to seal , keep water from entering the bilge, that is exerting ~1.6 pounds of pressure (.43# of hydrostatic head per foot of draft). The sealing surface, steel and carbide, are very wide producing a large surface area to seal and IMHO preform as advertised. Disclaimer I do not sell or install professionally.

There are boaters that hate them and boater that love them. Its you choice what to run in your boat, Good luck.

knuckelbuster said:

PackMule, Although there is a rush of water when you bumped the rubber, it is a testament to their sealing ability that the water stopped when they re-aligned. Enclosed is the PYI's description for installation and maintenance for their PSS seal. The site is well done and has a video for installation.

I can not comment on the need to add more pre-load because I do not know that number as it now. If is were me, I would slide the coller back until the seal starts to leak and add the pre-load that the spec call for. that

PSS Shaft Seal: The world’s leading dripless seal.
My experience with these type 1 seal was from processing equipment. From my experience, seal of this type can overcome some misalignment (<.030) and contamination(< 5% TDS) of the liquid in the sealing area. Perfect for the boating environment.

This seal in question has to seal , keep water from entering the bilge, that is exerting ~1.6 pounds of pressure (.43# of hydrostatic head per foot of draft). The sealing surface, steel and carbide, are very wide producing a large surface area to seal and IMHO preform as advertised. Disclaimer I do not sell or install professionally.

There are boaters that hate them and boater that love them. Its you choice what to run in your boat, Good luck.

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Thanks for the info. I'm not sure what brand of seal I have. For some reason I only have 2 clamps on my belows and they are at the same end,the stern tube end.I'm going to the boat again tonight and make sure .I wonder if some brands might have the belows molded to the carbon and only clamped on one end.

Tom.B said:

There is a story there that I am sure I'm not alone in wanting to hear. Can you elaborate?

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Tom,
I'm a little reluctant to put something as negative as this out but he deserves it.
I bought a flexible coupling for my Albin w Yanmar and they must have sold me one for a 20hp engine instead of my 34hp engine. The thrust on the Propeller shaft was enough to push the hex heads of the bolts far enough fwd to make them hammer on the gear box coupling. That ruined bearings in the gear such that I needed to replace it. $800.
When I presented my case to the owner (of PYI (13 years ago)) he came at me like a mad animal yelling on and on about how wrong I was. I was shaking from the experience .. Just being on the receiving end. It was his call to use the coupling I did and the cause of the damage was clear ..... I showed the parts to at least one mechanic and they agreed that the coupling used was for a lower power engine.
That guy was so abrasive I just ate it and bought a new gear from Cascade Engines in Seattle.
So I don't recommend them. However the company could have been sold several times since then ?????
As far as I know their products are great but as I recall most that I was interested in were R&D out of the UK.
To solve my problem w the Albin I bought a new gear from Cascade and another flex coupling (one stet up from the old coupling) from another source and went on boating. I did, however check the coupling for marks frequently for a time.

Pack Mule said:

Thanks for the info. I'm not sure what brand of seal I have. For some reason I only have 2 clamps on my belows and they are at the same end,the stern tube end.I'm going to the boat again tonight and make sure .I wonder if some brands might have the belows molded to the carbon and only clamped on one end.

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My seal is fine .It has all 4 clamps on it . I understand how it works now . Thanks guys .

Pack Mule said:

I understand how it works now . Thanks guys .

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Ditto...4 clamps.

IntervaleII said:

Another option for those who are considering installing a dripless shaft seal is Tides Marine, shaft seals. You are able to put an extra seal on the shaft which allows you to change out the seal if it starts to leak while in the water.
Just another option

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That is exactly what my yard guy did. I was replacing both of my shafts so he said that while they were out, the seals are cheap and the labor is already being paid for...and while he was at it, he put an extra seal on the shaft. I thought it was a great idea!!!!

I like the PSS (PYI), have had them on 2 prior boats and am going into the yard next week to have them put on this boat. I have also had the traditionaly stuffing-boxes, which work, but in my opinion are not ideal as they are intended to weep, which means water into the bilge. The area inside the bellows need to be cleaned periodically, so being able to pull them back and get a flow of water is in my opinion, very helpful and probably intentional. Bits of dirt accumulated in there. You also have to be careful not to over-tension them, much the same as you never compress the daylights out of the more traditional stuffing-boxes.