Maintenance of PSS Shaft Seal - Re-post

Terry in Naples · Mar 14, 2012

pss shaft seal

I have a shaft seal and have had to compress the bellows a time or two. I just loosened the clamps and pushed the belows up on the shaft compressing the belows retightened. worked for me.

bria46 · Mar 14, 2012

Again, Check with the manufacturer-before you do any adjustments to your Shaft Seal. I'd hate to see you sink your boat either underway, at anchor or in your slip!

juslookin · Mar 14, 2012

PSS

Recommends inspection of the bellows on a regular basis. There is some weakening of the bellows to be expected. They do I think, recommend replacement at some interval, but not sure what it is. Maybe 5 years. I would tighten it slightly if there is some water intrusion.

seadaddler · Mar 14, 2012

Leaking

My seal started leaking and got worse spraying water all over,I did mine when on the hard for a new bottom paint job.
I contacted PSS for help and got a set of new set screws and just compressed it a 1/2'' or 1'' and than added the new set screws and been good so far and did not touch the bellows clamps at all.
I also viewed the vedio on the PSS web sit.
Nick

orion · Mar 14, 2012

I have had my PSS in the boat for ten years. About 2 years ago I called PSS and asked about replacing the bellows. They said that the literature suggests five years. However, they also said that if there are no leaks the system will work indefintely. If there are leaks it will not be catostropic. There will only be pinhole leaks.

DeniseO30 · Mar 14, 2012

It will be a mess of water, but pull the bellows back and wipe the surfaces with a fuzz free cloth. It only takes a tiny little spec of something to cause that slight leak.

31seahorse · Mar 14, 2012

Hello Steve,
Three years is not a long time for a PSS dripless. Working on it in the water will be exciting! I'll describe what I've done on two boats we have owned on which dripless shaft seals were in use, adjusted, or replaced by us.
Wiping the face of the meeting surfaces is a good, simple first step and can be done without removing anything.
Mark the location of the forward end of the collar on the shaft with a thin-point marker so you can judge the amount of compression you apply when you move the collar aft. I don't think you need to compress the seal very much to get a change....less than 1/2 inch would be plenty, I think. You will get a spray of water around the graphite (?) seal if you pull the stainless steel collar forward toward the engine. A rag to wrap the shaft temporarily might stem that flow enough to work on the collar.
I think the instructions mention checking compression of the bellows at some short intervals after adjustment. Hot and squeeling is not a good thing. If your dripless does not have the tube led upward from the graphite ring you might need to "burp" the seal by pushing aft on the bellows to let a bubble of air escape. That will spray some water into the area too.
There are two set screws in each threaded hole in the stainless steel collar if I remember correctly. There is at least one, maybe two rubber "O" rings within that collar against the shaft. You won't be able to remove the rings while the boat is in the water, but you could do that if the boat were out of the water. They could be lubricated with an appropriate "O" ring grease by putting the grease on the shaft before you moved the collar in either direction.
Of course, contact with the manufacturer for advice is always a good idea.
Respectfully, Phil

Chuckbear · Mar 14, 2012

Steve, Phil's post is right on the money. Wipe the surfaces with a clean rag first and see if it goes away. Often after setting for a while they get some stuff between the mating surfaces. I have installed hundreds of these over the years, including my own boat and many are still just fine after ten years. If you need to make an adjustment don't compress too much, that will actually make it leak. Also contact PYI and get a new set of set screws. Once they are tightened down the tips flatten out and can slip if reused. To prevent any possibility of the collars slipping we add a doughnut zinc to keep everything in place. You can see a photo here, http://tinyurl.com/82ora83 . Despite the rants that always come up whenever the dripless seal is mentioned, I have never seen one fail on its own. Chuck

Maine Sail · Mar 14, 2012

steve stark said:
Posted this in 'Musings' without response, so am cross-posting here in hopes of attracted the eye of an experienced salt...

I have a 2001 Hunter with a Yanmar 3gm30f. I had a PYI PSS seal installed 3 years ago and do a visual inspection at every use. I have noticed a small amount (1/4 cup or so) of water collected under the seal occasionally and am wondering if the yard put enough compression under the bellows. I am probably 2-3 years away from a bellows replacement but am contemplating re-compressing the bellows. I know from the excellent advice on this board to use new set screws. Now for the questions:

- In loosening the rotor, how best to lubricate the O-rings to slide it back to the neutral point, and then re-compress?
- Should I squirt liquid soap into the gap between the rotor and shaft on the coupling side? I guess I am worried that salt water on the bellows side may be putting a 'set' on the bellows side of the O-rings and if I try to move the rotor it might roll or otherwise distort the O-rings.
- Should I 'twist' the rotor axially while trying to move it longitudinally?

The shaft is fairly clean and bright between the rotor and coupling

As always, your most excellent advice is appreciated.

Should be no need for lubricant and yes twisting when compressing helps. You will however need new set screws if re-compressing. First make sure the surfaces are clean between carbon and rotor. Also check your motor mounts. They may be worn and allowing the engine to ride forward more than they should..

jsgonz · Mar 14, 2012

At the risk of using the wrong tread for this question, with a PYI PSS seal, how do you adjust your engine alignment? The pressure of the bellow causes the coupler to be hard against the transmission output flange. Loosening the coupler by taking three bolts off and the fourth loosened, it is still hard against the flange, and I cannot see even putting a feeler gauge between the two to ck if there is a gap for an adjustment of the motor mounts. Plus the coupler has a groove ( male groove) that locks in the output flange so that it locks in place with the bellow pressure against it.

If I take out the set screw from the stainless collar and allow the collar to slide forward to relieve the pressure on the flange, I risk water coming into the boat and having an real problem on my hands. With vibration at 2000 RPMs that I would like to smooth out, how do I adjust alignment with the dripless seal? Any thoughts from Main Sail, my go guy on esoteric questions, or any one else with experience?

By the way, I had the prop ck'd before installing the new strut, cutless bearing and shaft,

Maine Sail · Mar 14, 2012

jsgonz said:
At the risk of using the wrong tread for this question, with a PYI PSS seal, how do you adjust your engine alignment? The pressure of the bellow causes the coupler to be hard against the transmission output flange. Loosening the coupler by taking three bolts off and the fourth loosened, it is still hard against the flange, and I cannot see even putting a feeler gauge between the two to ck if there is a gap for an adjustment of the motor mounts. Plus the coupler has a groove ( male groove) that locks in the output flange so that it locks in place with the bellow pressure against it.

If I take out the set screw from the stainless collar and allow the collar to slide forward to relieve the pressure on the flange, I risk water coming into the boat and having an real problem on my hands. With vibration at 2000 RPMs that I would like to smooth out, how do I adjust alignment with the dripless seal? Any thoughts from Main Sail, my go guy on esoteric questions, or any one else with experience?

By the way, I had the prop ck'd before installing the new strut, cutless bearing and shaft,

Actually, it makes it easier. The seal does not have the strength to move the shaft out of straight and thus it makes for inserting feeler gauges much easier as it keeps the perfect light pressure on the flanges. You need to press/hold the two flanges together anyway, but not too hard, in order to check the alignment. The PSS acts as a third hand and does this for you at just about the perfect pressure. Aligning boats with PSS seals I find is considerably easier than boats without as I have an extra helper..

Don12364 · Mar 14, 2012

Check First Using A Fixed Dimension.

There is a fixed dimension required between the rotor and the back end of the rubber moulding. It is easy to check this BEFORE attempting to move the rotor along the shaft. Others have pointed out the pitfalls in moving the rotor unnecessarily. From the PYI dimensions list all the 1" shaft units need to be 6.225" overall in the compressed state. Easy to check!
http://www.pyiinc.com/images/pdf/pss/PYI_PSS_Catalog_2011.pdf

Remember that in forward gear the shaft is pushing the engine forward on its AV mountings and reducing the compression of the bellows. In reverse the engine moves aft and increases this compression. Any weakness in the AV mounts will allow the engine to move more than specification.
Any undue wobble or vibration can momentarily unseat the seal and allow water ingress. Also, if you have realigned the engine at any time then it could have been moved fore or aft thus spoiling the original compression.

alexco38 · Mar 15, 2012

Re: Check First Using A Fixed Dimension.

I used a hose clamp on the shaft as insurance for the SS collar sliding.
I heard that PYI has a split collar for that purpose.

jsgonz · Mar 15, 2012

Thanks for the responses. I must have too much compression on the bellow. For a 1" shaft, it calls for 3/4" compression. I posted the picture of the PSS in the boat information section of this site. Click on hunter 28.5 and there is a group of picture for Mi Novia, that will show the seal. You will see how little room I have from the split collar, to keep the shaft from backing out, and the coupler. But I can tell you, I cannot appreciate any loosening of the coupler to flange when I take the bolts off to ck the gap with a feeler gauge. It is tight against it. I wonder now if I have over compressed the bellow.

nick8489 · Mar 17, 2012

PSS seals and the Luddites

Good to see this thread concluding without all the Luddites coming out of the woodwork and telling us how our boats are all going to sink. Ten years ago we would have been innundated with unwanted advice. Times change!

Kite Runner · May 14, 2012

Re: Check First Using A Fixed Dimension.

Did the same with mine...hose clamp. Another application is a 1" zinc anode.