Got a Dripless Shaft Seal?

[partingclouds]

There's a PSS dripless shaft seal on my boat whose age is unknown. I've had it for five years, and the bellows still looks to be pristine. I know it's recommended that it be replaced after six years, and l plan to do that on the next haulout. My question is, could the life of the new nitrile seal be extended somehow? Or should l just bite the bullet every six years?

[sailorboy1]

All i say from experience is that you aren't going to happy when the bellows fails.

[partingclouds]

What happened, Sailorboy? A catastrophic failure, or just a little water seeping through a crack? How old was the PSS unit on your boat? Any information would be helpful. I'd like to avoid a bad surprise.

[sailorboy1]

It cracked and was spraying water. Good thing i came to to the boat that day in mid week. Was able to stop by wrapping with rescue tape. Bet it would have jsy kept getting longer. Don't know how old it was as only had boat a year, but may have been original at 10 years old. The bellows design bugged me enough that i replaced with different type, which has always leaked from the seal. Next haul out I am going to packing.

[GreenWave]

Originally Posted by partingclouds

There's a PSS dripless shaft seal on my boat whose age is unknown. I've had it for five years, and the bellows still looks to be pristine. I know it's recommended that it be replaced after six years, and l plan to do that on the next haulout. My question is, could the life of the new nitrile seal be extended somehow? Or should l just bite the bullet every six years?

If you are not sure of the age just replace it with same. Not that expensive to do, especially if you do it yourself. You will need to be out of the water to do a full replacement.

[Tomodore]

PSS says every 6 years that is a reasonable span for such a critical piece of gear. Make sure to change hose clamps also. We have had some hose clamp failures around the engine lately probably due to salt water a couple years ago from anti siphon valve failure.

[Scubaseas]

I changed my last boot after 22 years and it still looked OK... BUT it can't hurt to do it, and it's not that hard as long as the coupler comes off. Change the boot, seals, o-rings and set screws. Make sure to "burp" the air out of it after launching.

Put anti-seize compound between coupler and shaft on reassembly.

It's possible mine lasted so long as no oil or grease ever got on it.

[blubaju]

Actually the spring inside softened somewhat, after tensioning it was fine again, now in it's 10th year and that should probably come to the end of the safety margin. Might still not be end of life, but one never knows. I am NOT advocating this, it happened not intentionally, but Radical Prostatectomy, triple heart bypass and now Covid-19 kept me away from my boat for 4 years now, boat boy (and co-builder) caring.

[stormalong]

I replace mine every 10 years. Have has the same boat for 30 years now.

One suggestion, if you have not used the engine in s long time burp the bellows to make sure the two parts are not stuck together. I keep the boat in the water over the winter and the two faces stick together. It is a lot of stress on the bellows to put it in gear to break it free.

[Clivevon]

Good thread & good reminder, thanks.

[Traitch]

I replaced the stuffing box on my 1974 Tanzer 28 in 1983 with a dripless shaft seal, two engines later and 38 years experience, including three round trips on the ICW, with thousands of hours of operation I am completely satisfied with their performance. They do need adjustment after hundreds of hours of operation from time to time and as noted earlier replacement of the flexible seal. I plan to replace my PSS Shaft Seal at my next haul-out. It will have about 700 hours on it and was installed in 2016 following my last engine install. Still working flawlessly so far.

[bongo]

Originally Posted by stormalong

I replace mine every 10 years. Have has the same boat for 30 years now.

One suggestion, if you have not used the engine in s long time burp the bellows to make sure the two parts are not stuck together. I keep the boat in the water over the winter and the two faces stick together. It is a lot of stress on the bellows to put it in gear to break it free.

I’m changing mine out right now. Mine was 13 years old and looks fine, (a little more compressed than when new). With a V-drive it is under a 4-108 so it has seen oil. Early on I cut a water bottle into a cylinder with a full length slit down one side, and put it around the bellows slit side down. It kept oil off of it, and, if there ever was any water droplets, would keep them from spraying up on the bottom of the engine/transmission. The plastic cylinder is very light and fits loosely around the bellows with no friction. Would burp as stormalong stated.

Good Luck, Greg

[stormalong]

Originally Posted by bongo

I’m changing mine out right now. Mine was 13 years old and looks fine, (a little more compressed than when new). With a V-drive it is under a 4-108 so it has seen oil. Early on I cut a water bottle into a cylinder with a full length slit down one side, and put it around the bellows slit side down. It kept oil off of it, and, if there ever was any water droplets, would keep them from spraying up on the bottom of the engine/transmission. The plastic cylinder is very light and fits loosely around the bellows with no friction. Would burp as stormalong stated.

Good Luck, Greg

Greg, I also have a V drive. I know what a pain access is to service it and even to reach to burp it. I take the transmission off to get at it -easier than removing the prop shaft.

The last time I serviced it was two years ago and the old bellows looked good enough to keep as a spare. Water bottle sounds like a good idea. Also a secondary clamp (hose clamp, clamping collar) is a good idea to be sure the rotor doesn't slip.

PS. Used to have a 4-108. Replaced it many years ago. I don't miss the oil drips :-).

[CCCruiser]

Originally Posted by Tomodore

PSS says every 6 years that is a reasonable span for such a critical piece of gear. Make sure to change hose clamps also. We have had some hose clamp failures around the engine lately probably due to salt water a couple years ago from anti siphon valve failure.

I was told by a PSS rep that battery acid vapors are the main concern in attacking the bellows. I surmise that oil drips are just as bad. In my case the batteries are in a separate compartment from the PSS Shaft Seal. I have had two instances across both of my owned boats where the locking screws did not prevent the rotor from slipping a bit. I've now installed the backup clamp to help prevent this type of issue. But these are not install and forget devices. A monthly (weekly if travelling a lot) inspection should be part of any good service practice. My local yard expert recommends 1/2" compression.

[Journeyman]

Is it oil dripping on the bellows that is bad? I thought it was oil dripping on the face seal itself. Can’t see how oil drips would hurt the bellows much.