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Old 01-23-2011, 09:21 PM   #41
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RE: PSS Dripless Shaft Seal Maintenance

Taras, is the vent line hooked up and not blocked?* The vent is designed to allow the air to evacuate the bellows.* If it is blocked, the bearing runs dry and you'll get a great deal of wear very quickly.
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Old 01-25-2011, 08:51 AM   #42
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RE: PSS Dripless Shaft Seal Maintenance

Our drip-less has a small hose from the raw water that pumps water into the bellows to lubricated the bearing.* The reason I was told is; as the boat increase speed a vacuum is created that sucks the water out the tube so raw water has to be pumped in and*the stern cutlass bearing holder has forward facing scoops to force water into the bearing.** So you might want to plumb pressurized raw water to the drip-less.


*
I switch to a drip-less as I was told that even if the shaft was teaks it would not leak because of the bellows.* Not sure if this is true but sounded good to me as I am planning for going a ground and/or beggaring up the prop/shaft.* Been a soft ground twice and on very low tides at our dock we sit on the bottom.** *****
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Old 01-25-2011, 12:10 PM   #43
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RE: PSS Dripless Shaft Seal Maintenance

You really don't need the "vent" attached to the raw water flow unless the boat is capable of powering over 12 knots, which is the threshold PYI uses. If you are borderline, I recommend the connection be made. Under 12 knots does not need a vent and in many cases has a plug in the hole. But without the vent and under certain circumstances the bellows needs to be burped, or the air purged from it. This needs to be done every time the boat is hauled, or in the case of a sailboat, if the boat heals over enough to allow air around the shaft log. A proper vent line eliminates this. Chuck
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Old 01-25-2011, 05:04 PM   #44
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RE: PSS Dripless Shaft Seal Maintenance

"You really don't need the "vent" attached to the raw water flow unless the boat is capable of powering over 12 knots."

Without the vent, burping the bellows is mandatory.* Forget, and you'll cause damage.* I found this out the hard way, and installed the vent.* If you burp the bellows, you should be ok, but vent installation is mandatory for speeds over 12 knots, per the instructions.
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Old 01-25-2011, 06:09 PM   #45
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RE: PSS Dripless Shaft Seal Maintenance

Quote:
Delfin wrote:

"You really don't need the "vent" attached to the raw water flow unless the boat is capable of powering over 12 knots."

Without the vent, burping the bellows is mandatory.* Forget, and you'll cause damage.* I found this out the hard way, and installed the vent.* If you burp the bellows, you should be ok, but vent installation is mandatory for speeds over 12 knots, per the instructions.
That is pretty much what I said. Chuck

*
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Old 01-25-2011, 07:06 PM   #46
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RE: PSS Dripless Shaft Seal Maintenance

Close enough Chuck, except that without the vent, you don't need to vent the bellows "under certain circumstances", you always do if the boat has been out of the water for a day or two, and not the "generally three months" or more that PSS says in their installation instructions.* There is nothing to keep the seawater in the stern tube once the boat is hauled, since the cutlass bearing drains allows the water to drain freely.* Once put back in the water, there is no way to get water to the forward cutlass bearing without burping.

At least that is my experience.
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Old 01-25-2011, 07:42 PM   #47
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PSS Dripless Shaft Seal Maintenance

Quote:
Capn Chuck wrote:

You really don't need the "vent" attached to the raw water flow unless the boat is capable of powering over 12 knots, which is the threshold PYI uses. If you are borderline, I recommend the connection be made. Under 12 knots does not need a vent and in many cases has a plug in the hole. But without the vent and under certain circumstances the bellows needs to be burped, or the air purged from it. This needs to be done every time the boat is hauled, or in the case of a sailboat, if the boat heals over enough to allow air around the shaft log. A proper vent line eliminates this. Chuck
And that is what I said, so I am confused. I think I have only installed a couple of hundred of these. Chuck

*


-- Edited by Capn Chuck on Tuesday 25th of January 2011 08:43:17 PM

-- Edited by Capn Chuck on Tuesday 25th of January 2011 08:43:57 PM
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Old 01-25-2011, 07:50 PM   #48
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RE: PSS Dripless Shaft Seal Maintenance

Chuck, my apologies if you thought I was arguing with you.* The tone of your post seemed to indicate that installation of the vent line was optional, since you indicated that there were "borderline" cases where it might not be needed.* I don't think so, but you have clarified that is not what you meant.
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Old 01-25-2011, 08:31 PM   #49
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RE: PSS Dripless Shaft Seal Maintenance

So the vent is really there to insure air does not get trapped and the seal run dry?

On my boat it is plumbed to the*raw engine cooling water, but being basically a slow boat that vent can be just left open as long as it is well above the waterline.

Is there are advantage one way or the other?* open to the atmosphere or plumbed to water?*** JohnP
*
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Old 01-26-2011, 06:13 AM   #50
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RE: PSS Dripless Shaft Seal Maintenance

Steve
One signigificant factor in using the PSS system is that if you do NOT have a water feed tube to it, then when you haul the boat water will drain from it. Now when you launch the boat, there is an air pocket inside the PSS bellows. You HAVE to compress it by hand to "burp it" in order to let the water out. If you dont, you can burn it up.

They took care of this in recent years by adding the optional water feed tube to the top of the bellows. In 2007 when I replaced mine, I chose the water feed tube. Its not required for slow trawlers like ours, but I didnt want to have to remember to burp it.

In 2007 when we surveyed and then bought our boat, our PSS was never burped. I dont think the owner knew it was supposed to. The rotor had rust on it and it leaked slightly when the shaft turned. It was bone dry at rest. So I replaced it.

People ask how long do they last? Mine lasted 4000 engine hours and about 7 years.
Before I replaced mine I spoke with Dan Schalk, the lead engineer for the PSS system at PYI. He suggested that I take some fine wet sand paper and try to resurface the face of the bellows as was already described below. However, I found that when I tried to insert the paper, the incoming water pressure made it very difficult. It was messy. So I simply deceided it was time to replace it.
Its been very good ever since.

You can see my PSS installation with the water tube to it here
http://tinyurl.com/2e9ou5y
which is an article I wrote that has some pictures that show the PSS.
R.
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Old 01-26-2011, 06:44 AM   #51
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RE: PSS Dripless Shaft Seal Maintenance

But the old waxed packing seal is more secure given a small bit of maintenance.

And the modern Goretex is a one time install , adjust then forget.

Why put the boat at risk for a one time job?
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Old 01-28-2011, 02:13 PM   #52
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RE: PSS Dripless Shaft Seal Maintenance

All,
what a great post!* I have learned so much about my dripless shafts.
Thank you for all the great information.

I do have a water line going to my dripless shaft and I did check it to be sure it was not plugged or anything.

I guess since I have now burped the seal, that all should be fine???** I will keep a close eye on it and if any additional metal shaving appear, then it will be time for more investigation.

Steve
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