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-   -   PYI dripless seal leaking (http://www.sailnet.com/forums/gear-maintenance/61184-pyi-dripless-seal-leaking.html)

drynoc 01-10-2010 07:10 PM

PYI dripless seal leaking
 
My dripless shaft seal is leaking at the point where the rubber ends and meets the shaft. I can grab that point and shake it and make the leak either worse or better. How can that happen? Is there some adjustment or tightening I can do? If not, what is the fix? Thanks.

CaptainDan99 01-10-2010 07:31 PM

PYS dripless seal leak
 
I have the PYI seal and it has been working great for 5 years. If you pull back on the rubber bellows away from the stainless doughnut on the shaft, it will leak. At one point, some crud built up on the stainless doughnut and as per the manufacturer suggestion, I removed it from the shaft and cleaned it with 600 grit sandpaper. No problems since that time.

Dan

erps 01-10-2010 08:07 PM

The rubber bellows ends at two places. It's clamped to the shaft log with a hose clamp on one end and it's clamped to a carbon seal ring on the other end. Make sure both hose clamps are tight. The carbon seal ring butts up against a stainless steel collar. The stainless steel collar needs to push against the carbon seal with enough force to keep the water outside your boat. Too little pressure will cause a leak. So will a piece of grit or something in between the collar and carbon seal. The sand paper trick will clean any grit out. You might also grab the collar and try and slide it one way or the other to see if it's loose. A loose collar could back away from the carbon seal and cause a bad day. One other thing, the rubber bellows tube doesn't last forever. IIRC, it's recommended that it be replaced every ten years. I just replaced mine this summer after another member, JRD22, posted the recommended replacement interval.

CaptainDan99 01-10-2010 08:48 PM

Check out the instructions and videos at
PSS Shaft Seal

Ray is correct that the bellows need to be replaced every few years. Old bellows could reduce the pressure and cause the leak.

Dan

drynoc 01-11-2010 06:43 AM

Thanks, guys
 
The system was only installed five years ago, so I don't think it is due to have the bellows replaced. The leak is at the forward end where the bellows meets the stainless steel collar. I tightened the two hose clamps that are holding the bellows in place at the forward end, but that didn't seem to have any effect. I'll check out that link on the PYI site. The boat is in the water, so repairs will be minimal at this time.

LarryandSusanMacDonald 01-11-2010 07:45 AM

I've had mine on for 12 years and it still works fine. I talked to a PSS rep at the boat show one year and he said you just need to check the bellows every so often to make sure it's still soft plyable and not brittle. He said they'll probably last for 15 years or so but they don't put that in writing because it (a) hurts sales (b) could lead to lawsuits if a boat sinks because one fails and (c) hurts sales.

I'm not advising that you leave yours in as long as I have, because I don't want to be sued if your boat sinks. (Don't bother anyway - I'm not worth suing - always go after the deep pockets.)

I'm probably going to have mine changed out next time we pull it - next summer some time.

drynoc 01-11-2010 07:49 AM

One more thing
 
Erps,

You said that "too little pressure" in one place can cause a leak. If that is the problem, how would one go about adjusting it? I don't see any reference to that on the PYI web site.

Thanks.

erps 01-11-2010 08:46 AM

That's too little pressure where the stainless collar slides up against the carbon seal. I just redid mine this summer and it's my recollection that after installing the new bellows, the instructions called for sliding the collar up to the carbon seal until it made contact and then sliding it another inch to compress the rubber bellows. How far you extra you slid the collar depended on the diameter of your shaft. I made a mark on the shaft with an indelible marker just aft of the collar so I could tell if the collar started creeping back away from the carbon seal.

Maine Sail 01-11-2010 09:33 AM

If the hose clams are snug then it is most likely a compression issue or crud between the carbon and stainless faces..

There are two set screw holes in the stainless rotor located at roughly 10:00 & 2:00. There should be two set screws in each hole, one on top of the other.

Remove the set screws and back the rotor off until it is just touching the carbon face but there is no compression in the bellows. Mark your shaft with electrical tape, at the forward edge of the stainless rotor, then slide the rotor towards the stern using the compression distance, for your dia, shaft from the PYI instructions.

If you don't REPLACE the set screws there is no guarantee they will bite the shaft as the volcano head gets rolled or flattened!

These are new:
http://www.pbase.com/mainecruising/image/108673734.jpg

You then REPLACE the set screws with new and re-tighten them at the newly measured compression distance from the tape you placed.



This is a photo where you can see the set screw holes in the stainless rotor..
http://www.pbase.com/mainecruising/image/72621935.jpg

I then place a 316 SS Ruland split collar behind the stainless rotor as added insurance to prevent the rotor from sliding forward. These are available from McMaster-Carr.
http://www.pbase.com/mainecruising/image/108673974.jpg


Ruland Split Collar installed on a v-drive boat. Note the white tape where the compression measurement was taken off.
http://www.pbase.com/mainecruising/image/120505368.jpg

P.S. could just be as simple as some junk caught between the face seals..

deniseO30 01-11-2010 09:45 AM

well, since no one really answered you drynoc. :) are the 2 clamps really tight? we always put them so that the screw part is 180* opposite of the other. Being in the water is a problem because you could sink your boat if you loosen those and the whole mess pops apart! Possibly you can find clamps that are wider, and replace one then the other?


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