PSS Seal Maintenance

Dripless shaft seals are extremely low maintenance, so for many people they aren't top of mind when they're doing their engine room inspections. Posting this to increase awareness for those who are less experienced.

After my recent incident where the fuel filter canister developed a crack and sprayed diesel all over the engine room, I had a large clean up task on my hands. During that clean up I got up close and personal with the shaft seals, and I noticed that one had very slight cracking on the surface.


I didn't love that, but I also wasn't looking forward to paying for a haul. Nonetheless it seemed like the prudent thing to do so I had it done. BTW that picture was after they had been removed - the cracking wasn't even that obvious when they were in place.

Boy am I glad I made that choice. Once removed I got the chance to bend the bellows. Holy cow, those cracks were deep!



Just the slightest bend showed how extensive those were. Of course you can't bend it when it's on the shaft, so I couldn't see that. I will feel so much better now knowing that those are replaced, and I'll change my inspection routine to include a closer examination of the seals.

BD

BDofMSP said:

Dripless shaft seals are extremely low maintenance, so for many people they aren't top of mind when they're doing their engine room inspections. Posting this to increase awareness for those who are less experienced.

After my recent incident where the fuel filter canister developed a crack and sprayed diesel all over the engine room, I had a large clean up task on my hands. During that clean up I got up close and personal with the shaft seals, and I noticed that one had very slight cracking on the surface.

View attachment 156376
I didn't love that, but I also wasn't looking forward to paying for a haul. Nonetheless it seemed like the prudent thing to do so I had it done. BTW that picture was after they had been removed - the cracking wasn't even that obvious when they were in place.

Boy am I glad I made that choice. Once removed I got the chance to bend the bellows. Holy cow, those cracks were deep!
View attachment 156377


Just the slightest bend showed how extensive those were. Of course you can't bend it when it's on the shaft, so I couldn't see that. I will feel so much better now knowing that those are replaced, and I'll change my inspection routine to include a closer examination of the seals.

BD

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Any idea on the age of the bellows?

They were about 14 years old.

BDofMSP said:

They were about 14 years old.

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Roughly what was the total cost to have them changed?

Good catch.

dhays said:

Roughly what was the total cost to have them changed?

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Twin engine so two of them. Replaced with the Pro series which are far more substantial. With haul about 3 boat bucks.

14 years is way beyond what I would consider ordinary service life. I’m glad you addressed it before it caused any harm… except that dent in your wallet.

BDofMSP said:

They were about 14 years old.

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That’s a bit past their due date. Glad you caught it, good job!

This is something that I need to look at having done the next time I do a haul out.

TF is valuable for so many reasons. A big one for me is that it reminds of stuff that I forget about.

Nice catch! Hope you replaced the bellows with the blue silicone ones.

Think the black rubber ones are rated 5 or 6 years. I replaced the bellows kit on mine after 8 seasons, 6,000 hours.

Ted

dhays said:

This is something that I need to look at having done the next time I do a haul out.

TF is valuable for so many reasons. A big one for me is that it reminds of stuff that I forget about.

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That was the intent of this post. My ownership would be a disaster if I hadn't had the guidance that I've got from this forum. I take 100 times what i get, but I hope I can contribute something to help the balance.

O C Diver said:

Nice catch! Hope you replaced the bellows with the blue silicone ones.

Think the black rubber ones are rated 5 or 6 years. I replaced the bellows kit on mine after 8 seasons, 6,000 hours.

Ted

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They're still black on the outside but they're the full fabric impregnated silicone design with the 10 year service recommendation vs 6 for the standard model different design with a keeper ring outside the normal seal too. Well worth the $100ish extra for the part. My mechanic said he won't use the lesser version unless the customer signs off insisting on it.

The other shaft BTW? Perfect. Bend it and zero cracks. Who knows why one would age so differently than the other? But I'd love to know.

BDofMSP said:

The other shaft BTW? Perfect. Bend it and zero cracks. Who knows why one would age so differently than the other? But I'd love to know.

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If they were from the same batch of hoses, it may have to do with chemicals used near one hose and not the other. Some chemicals dry rubber out to the point where it can crack more quickly. Lacquer thinner or acetone come to mind.

Ted

Have come to greatly prefer Tides with O rings to PYI products. Have used PSS for decades but requires haul should anything be past it’s due date or be injured. With the tides you can have multiple spare O rings left on the shaft. So replacement can be done in the water. Also less dependent upon bellows compression and cooling water. Once had issue with the water tube getting kinked. Fortunately caught in time.
For small engines there’s much to say for simple stuffing boxes. Modern stuffing works great.

I am new and still learning, so, I have an ignorant question due to lack of knowledge. I am assuming you have to haul out to change dripless seal boot. If anyone has changed a CV axle shaft, years ago you had to pull the whole axle. Then they came up with a boot that was like a clam shell, secured on each end and then in the middle the length of the boot it had molded in the rubber metal on both sides that screwed together to seal it . Is that an option in this situation or something manufacturer's have chosen not to develope.

Interesting....how hot does your engine room get? Or any ozone generating equipment around the seals?

Had PSS seals on the assistance tow boat that I drove for around 13 years. Never had bellows cracking happen, even after all that time. Easy to detect because on that boat when checking the oil, the bellows was only a couple feet from your face.

That boat went through one or two carbon seals due to the excessive shallow water operations generating TONS of sand being sucked in and helping their premature deterioration.

Dnnsmrgn said:

I am new and still learning, so, I have an ignorant question due to lack of knowledge. I am assuming you have to haul out to change dripless seal boot. If anyone has changed a CV axle shaft, years ago you had to pull the whole axle. Then they came up with a boot that was like a clam shell, secured on each end and then in the middle the length of the boot it had molded in the rubber metal on both sides that screwed together to seal it . Is that an option in this situation or something manufacturer's have chosen not to develope.

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Haven’t heard of any like that, and I’d be hesitant to install one. Too many opportunities for failure.

psneeld said:

Interesting....how hot does your engine room get? Or any ozone generating equipment around the seals?

Had PSS seals on the assistance tow boat that I drove for around 13 years. Never had bellows cracking happen, even after all that time. Easy to detect because on that boat when checking the oil, the bellows was only a couple feet from your face.

That boat went through one or two carbon seals due to the excessive shallow water operations generating TONS of sand being sucked in and helping their premature deterioration.

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We boat on the upper Great Lakes so ER temps are typically 102 or less ... often lots less. I've never intentionally used ozone in the engine room but have used it in the forward cabin twice in the past 5 years. Not sure what else generates ozone on it's own?

Not sure myself what all will produce ozone, but anything that sparks like an electric motor with brushes reportedly does. Sparks in general can, so maybe relays that arc.

Also not sure if some propellants in spray cans can affect the silicone or rubber in the seals.

No matter, probably all of those things don't amount to much.... but as I posted, never say that kind on cracking on the PSS seals that were used in our small fleet of boats.