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Old 25-03-2007, 09:35   #1
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Shaft Seal ?'S

I have an '84 Hunter 37-C with a PSS shaft seal installed by the previous owner. It has worked fine for the two years that we've owned the boat, but now has started to leak from between the delrin bearing and the stainless donut that is fixed to the shaft. I've tried cleaning any debris that might have become lodged in there to no avail. Maybe time for a replacement? Does anyone have experience with other dripless shaft seals that are out there - in particular I've seen one that uses ATF for lubricant inside a housing that is attached to the through hull and the shaft spins through 3 seperate rubber seals. Don't remember the name but it seems like a better idea than the PSS. We're planning on leaving her in the water unattended for up to 6 months at a time while we're out of the country working so can't have any little drips. Any input is greatly appreciated. Thanx.
Scott
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Old 25-03-2007, 11:33   #2
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I can't comment on other brands but my PSS has worked flawlessly for several years. It may just need the donut adjusted.
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Old 25-03-2007, 13:23   #3
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westykids how old is the system. pss has updated with a ventline that has to go at least a foot above water line in center of boat preferrable. if you haul your boat for the winter you are supposed to pull the bellows back (this is on all models to wet the contact surfaces. otherwise you will burn up to contact ring. the reason for the vent is so you do not get an air pocket at the seal location, preventing water from lubing and cooling the mating surfaces.
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Old 25-03-2007, 16:06   #4
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Scott, traditional ATF swells rubber parts and as a result, used car scoundrels will sometimes put it in a brake system to "seal" leaks when selling an old POS.

So, I wouldn't want to use a triple-sealed shaft that was designed to use a fluid that swells--and also rots--the same seals, assuming it is ATF and they are rubber.

A plain shaft log with GoreTex packing, or the teflon-clay type packing, seems to be the best answer for KISS.
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Old 25-03-2007, 18:28   #5
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Aproperly adjusted flax packing works great
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Old 25-03-2007, 21:15   #6
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Welcome aboard Westykids

Here is a thread that went into quite a bit of detail on the PSS. This should help you decide what you want to do.

Hate to say it!
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Old 26-03-2007, 08:53   #7
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Thanks for all the input. As Amanda Grace is our one and only home, and an offshore cruiser, catastrophic failure of the system, though rare, is not an option. I'm leaning toward putting the old packing gland back in.
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Old 26-03-2007, 14:40   #8
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Quote:
Originally Posted by never monday
Aproperly adjusted flax packing works great
The key words are "Installed Properly"

And if not properly installed it can wear the shaft and eventually break and/or still leak. It all comes down to ones mechanical ability. Either one could fail.

If the flax type fails underway, one has to remove the nut, put in more packing and readjust and hopefully it reseals providing the shaft is still OK. I've seen some leaking so bad it was squirting out in a stream. You tighten it down and it gets worse. And some, the stupid nut won't turn it's all green and seized up. One has to have the special wrenches available and hope one can get the thing turning. Even then you have to be careful to not twist the gland hose or it'll fail too. And if the green has any red in it, that would concern me, as well.

If a PSS fails underway one has to slip the thrust ring up and stuff rags or ??? into the bellows to slowdown the flow and then repair it at a later time but the shaft will most likely be OK. BTW- a boat should ALWAYS have a good working bilge pump(s)!!!

If one has EZ access for visibility and work, seals can be monitored. It all comes down to ones capabilities. I feel safe with the PSS because I know what can go wrong and know how to deal with it. But I also installed it myself and know it was done properly. As above, the "key words" are what will make the difference on ANY installation.

If one gets questionable workmanship any seal, among other things, could fail. A boat built/maintained by the unskilled or skimpers will be if lesser quality.
............................................_/)
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Old 26-03-2007, 17:48   #9
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"If the flax type fails underway, "
Flax?! Please, flax packing may still come in new boats, but it is thoroughly obsoleted. Even in home plumbing and heating valves, flax is obsolete no matter how often it still ships.

And after all, has there ever been a "catastrophic failure" of a flax packing?<G>

I think if he repacks with a modern packing material in the old fashioned packing gland, he gets a combination of greatest reliability, lowest cost, and simplest system. A win-win all around, except for the guys who made the patent shaft seal.
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Old 26-03-2007, 19:04   #10
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Flax or gortex packing either work well when maintained and adjusted regularly. Replace the bronze gland every 20 or so years and make sure it's part of the bonding system also.
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Old 26-03-2007, 19:29   #11
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Quote:
Originally Posted by hellosailor
And after all, has there ever been a "catastrophic failure" of a flax packing?<G>
Yes!

Packings have been know to seize up on start up after sitting a long peroid and/or to have the packing TOO tight and seize up and then twisting it right of the shaft log.

If it were a fiberglass shaft log I'd be worried about the thing taking out the log. In which case would be worse then a PSS bellows breaking.

You would have to get the damn thing back on some how or move it out of the way to plug the hole. And with the thing froze up on the shaft and water pouring in that might be a bit fun especially if it has worn a grove in the shaft.

I can see it now
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Old 26-03-2007, 19:40   #12
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Del,
I hate to start an arguement, but. I can't see that as a plausible scenario the way I was taught.
Packing is always 3 seperate rings never a 3 wrap string. Packing should be changed every 5 years, minimum. Packing should be adjusted when a drip is noticed at rest without the shaft spinning.
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Old 26-03-2007, 20:01   #13
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It's not a "plausible scenario", I've seen it happen! It's Not an argument, just an FYI of experiences! I've spent my fair share of time in the bilges of ships and boats and seeing is believing. If one were to take care of their boat the way they should, nothing would happen, theoreticly (sp).

It happens on the multi stage pumps too. The old ones, anyway.
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Old 26-03-2007, 20:18   #14
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i'm a flax guy, but i guess it's what i am used to so i stick with it. I've never had any issues and have always managed to dig it out and replace it when needed with little trouble or time invested.

I've never heard any complaints about the PSS, in fact the people i've spoken to that use them swear by them. i did ask my local prop shop (bobby soles) about the dripless and they said if you have any gouges or scars on the shaft it won't seal (indicating the flax would) but i have no first hand experience there.
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Old 26-03-2007, 20:40   #15
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Quote:
Originally Posted by Latitude9.5
I've never heard any complaints about the PSS, in fact the people i've spoken to that use them swear by them. i did ask my local prop shop (bobby soles) about the dripless and they said if you have any gouges or scars on the shaft it won't seal (indicating the flax would) but i have no first hand experience there.
Correct! "gouges or scars" Over a certain depth. An o-ring will seal against minor abrasions. Again "Installed Properly"

Don't get me wrong I have nothing against the packing type seals, they've worked for hundreds of years. But pumps have gone to the face seals, mostly due to the heat and wear factor and the ease of replacement in most situations.

And the packing has evolved to the teflon stuff for a lot of pumps and valves that don't have a heat problem.
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