Replacing PSS shaft seal bellows

[John Langford]

I have had a PSS shaft seal since 1999. It works fine and I inspect it regularly for any sign of deterioration in the bellows or the graphite facing. No problem that I can see. The bellows don't look or feel brittle and there are no signs of cracking. The area aft of the engine in Calypso is very clean nad the bellows have never come into direct contact with oil or fuel. That said, the standard advice is to change the bellows every 5 years or so. Before I contemplate adding that task to my annual haulout this spring I would be interestd to know if others on the list have felt the need to replace their bellows as instructed or have experienced any form of deterioration in the bellows along the way.

[Ron Hill]

John : I have no experience with the life of PSS billows.
 
But I'd guess that it is similar to exceeding the expected life when considering your standing rigging.  When you finally have a failure it's real BIG Aw-Sh#t!!

You are well past twice the 5 year life!  Are you trying to go 3 times the life??

It's your boat, a thought

[John Langford]

No, I didn't see this as a contest, Ron. I am looking for an assessment of risk based on data. Some shaft seal users I have met argue that if the bellows are not exposed to fuel or nasty chemicals then the effective life span is much longer than 5 years. The more legally bent and sceptical among them argue further that the manufacturer's recommendation to replace the bellows every 5 years is largely designed to make money and reduce legal liability in the event of a failure. I am interested to know if other owners have had a shaft seal for much longer than 5 years - as I have - without the bellows showing any sign of deterioration.

Here's a question for a denizen of Chesapeake Bay that might not provoke so fierce a response.  I hauled my boat out one winter many years ago at a lovely little yard up Whitehall Creek near Annapolis. Is it still there?

[scotty]

Hi John.  I bought a boat in October of this year that had a PSS system.  It was the original installed in 2004 (the year the boat was built).  At 8 years old, it looked great, but I decided on general principals to replace it.  The boatyard told me that there was a more recent model that had the tube for "burping" that mine did not have.  Also I was glad to replace the collar, because I have heard that it is one source of failure (never re-use the set screws!!!).  I also added a hose clamp to the shaft as a safety to the collar. It cost me about $400, but I consider that cheap insurance, since it would be catastrophic if it failed.  Your description sounds like optimal conditions, but I wonder if the inside, or the ends, could wear in areas not easily seen.

[mainesail]

No, I didn't see this as a contest, Ron. I am looking for an assessment of risk based on data. Some shaft seal users I have met argue that if the bellows are not exposed to fuel or nasty chemicals then the effective life span is much longer than 5 years. The more legally bent and sceptical among them argue further that the manufacturer's recommendation to replace the bellows every 5 years is largely designed to make money and reduce legal liability in the event of a failure. I am interested to know if other owners have had a shaft seal for much longer than 5 years - as I have - without the bellows showing any sign of deterioration.

Here's a question for a denizen of Chesapeake Bay that might not provoke so fierce a response.  I hauled my boat out one winter many years ago at a lovely little yard up Whitehall Creek near Annapolis. Is it still there?

They do begin to lose "elasticity" as they get on in years. This can lead to the need for an adjustment until the adjustment no longer works. When the engine moves forward on the mounts under load there may not be the specified pressure on the rotor and it can mist or spray.. I have replaced a number of them and done side by side weight based compression tests then measured overall height. Beyond about 6 years the new bellows always has more elasticity.

While 5 years is conservative & safe I would not push one beyond 7 years personally.. Also if you have an older un-vented seal that has ever run dry the heat generated is not necessarily the best thing for the bellows.. 12 years is running on luck but also shows how well engineered these are.....

[Roc]

John,
My boat is just a few hull numbers away from yours, and I too have the PSS seal, still the original bellows from when I bought the boat new.  Like you, I've never spilled anything on it, and always drape towels over it if I'm checking the ATF or anything that might spill on it.  I know PYI has a maintenance kit for around $50 bucks at the boat shows.  Like you, I feel the 5 years PYI suggests is based on legal aspects and not true longevity.  I have the model with the self 'burping' vent, with a vent line attached leading up above the water line.  For the past few years, I've thought of replacing it, but it seems to run fine and I've always pushed it off for another year. 

[tonywright]

I replaced mine after 5 years. It had lost some elasticity like Mainesail says.  It seems too critical a component to me to skip on the maintenance.  I replaced the collar for a vented one at the time, replaced for free by PYI when they shipped the new bellows.

Note to those who have the standard set-up: I also replaced the hose around a standard coupling on my previous boat (vintage 87) because I noticed cracks in the outer rubber, although it was not leaking. Maybe it's overkill, but I feel safer doing this kind of maintenance.

Tony

[Ted Pounds]

John,
Like you, I feel the 5 years PYI suggests is based on legal aspects and not true longevity. 

Yes, the 5 years is conservative.  But since it's a critical component you want to be conservative.  As an engineer and a pilot I know there are good reasons for conservative margins.  The last thing you want to do is stress a critical component to failure.  Just my $.02....

[Momentum M]

Here's a 6 min video on how to proceed.

http://www.go2marine.com/productcenters/shaftseals/

[mainesail]

Here's a 6 min video on how to proceed.

http://www.go2marine.com/productcenters/shaftseals/

PLEASE note that a solid coupling should NEVER, EVER fit the way they show in that video!!! That is very poor guidance on the part of PYI....


PLEASE PAY ATTENTION TO KEITH IN THIS VIDEO. THIS IS HOW A SHAFT COUPLING NEEDS TO BE FIT.

Thank god someone gets it out there......
http://youtu.be/RyKUsnCymbY

[Ron Hill]

John : Both marinas in Whitehall creek are still there. 

[John Langford]

Thanks for the input everyone.

I assume that the concern expressed by Mainesail was with the ease with which the press fit half coupling slid on to the shaft in the PSS video. I have the split style half coupling so I appreciated the tips about the type of wedges used to open it up.

I am leaning towards changing the bellows this spring if for no other reason than the fact that if there was a catstrophic failure the insurance company would probably be all over me about the age of the bellows. I also have the older bellows without venting but I have never run the bellows dry. The eleasticity also feels good. There is no spurting and I haven't had to further compress the bellows to keep the boat dry.

[pablosgirl]

Hi John,

You are wise to consider what an insurance company may do in regard to exceeding the manufactures recommended maintenance intervals.  I have a co-worker that has a twin diesel inboard powerboat that had the shaft bellows fail on one of the engine shafts and the boat took on enough water to flood the engines and upholstery before some one noticed that the boat was sinking and the boat was save from going to the bottom.  At first look his insurance company refused to pay for the damage, stating that the failure was due to lack of maintenance and that he was responsible for any loss due to neglected maintenance.  Only when my co-work produced maintenance records showing that both shaft seals had been completely replace three years prior to the incident and that was within the manufactures recommended 5 year maintenance interval that they agreed to pay the claim.  There are two lessons here.  Read your insurance policy very closely and keep good maintenance records.

[captran]

We bought Voyager in 2001 and had the PSS installed and used it in the Bahamas for 5 summers.  We brought the boat back to the Northwest (by semi) and have used it ever since.  Like you, I keep the area clean and inspect.  The bellows looked fine but the last several years noticed graphite spray around the collar area.  I also found in certain conditions I had to burp it.  So this winter decided to bite the bullet and have it done.  But,as typical, one thing leads to another and the boat yard said the shaft had a slight bend and recommended replacing, and the new shaft seal "shaft gland has injector", and of course cutlass bearing needed replacing...long story short... $2,317.  B.O.A.T.

[Roc]

Randy,
How did the yard know that your shaft and a bend in it?  Did they take the whole shaft out?  Doesn't seem that the whole shaft needs to come out to just replace the bellows on the PSS seal.....just curious how they came up with all those other things that needed replacing.