Got a Dripless Shaft Seal?

[Dave Lochner]

I just replaced the seal on my boat after 7 years. It is a small expense to keep the boat above water. Changed over to a split coupling too. The next change will be easier.

When shopping for the new boot, you will notice the sizes are in pairs, like "fits 2" and 2 ⅛" stern tubes. They do this with an insert that can be removed. No mention of this feature is made in the instruction manual nor on the website.

[Manateeman]

We switched to Last-Drop. In the water.
Very happy.
Mark and manatee crew.

[sailon46]

I had a Volvo drip less on the shaft of a Bene 51.4 cyclades. The surveyor in BVI did an out of water survey then launched her without burping the Volvo dripless yolk the boat out and push her to 3500 rpm. Bottom line the boat started leaking and almost sunk. Saved her with a 5 gallon bucket and a coffee can. You have to watch the drip less as a hawk. Fyi

[stormalong]

Originally Posted by sailon46

I had a Volvo drip less on the shaft of a Bene 51.4 cyclades. The surveyor in BVI did an out of water survey then launched her without burping the Volvo dripless yolk the boat out and push her to 3500 rpm. Bottom line the boat started leaking and almost sunk. Saved her with a 5 gallon bucket and a coffee can. You have to watch the drip less as a hawk. Fyi

The PSS has a "high speed" version. It has a hose fitting on the stator that can be plumbed into the sea water intake. The suction from the impeller pulls water into the PSS. There will not be a dry seal with this option.

[PineyWoodsPete]

This topic got me thinking about my 7 year old boat's Volvo water-lubed dripless seal. I've had it 2 years, never thought about it before, and no manual in the boat's papers. So I downloaded it, and see the rec. of lubricating it every 200 hrs or yearly with water-resistant grease, and replacing the seal after 500 hrs, or at least every fifth year. 450 hrs on the engine now, and I'm about to embark on an ~800nm round-trip from Monterey Bay to San Diego. Replacement means hauling out, which I plan to do this summer for bottom job.

Anyone with experience with these? The "lubrication"shown in the manual consists of just putting a bead of grease around the shaft exit from the seal - nothing about trying to work it inside. No drips at all so far...

[Marathon1150]

The plastic hose barb on our Volvo dripless shaft seal cracked and over a period of several months dripped enough water to fill the bilge to capacity. Unfortunately, our boat watcher did not notice and this led to all kinds of downstream problems, including corroded iron keel bolts on an iron keel (Beneteau).

We replaced the Volvo with a PSS and it has been problem free for the past 7 years. Somehow I missed that it should be replaced every 6 years so that will be job number one if and when we can get back to Papeete.

We pulled the boat to replace the Volvo seal. Later, a very skilled and knowledgeable marine technician told us two things after the job was done (by someone else). First, we could have just replaced the hose barb and second, we could have done the job with the boat in the water.

Has anybody replaced the PSS bellows without pulling the boat?

[PineyWoodsPete]

Originally Posted by Marathon1150

The plastic hose barb on our Volvo dripless shaft seal cracked and over a period of several months dripped enough water to fill the bilge to capacity. Unfortunately, our boat watcher did not notice and this led to all kinds of downstream problems, including corroded iron keel bolts on an iron keel (Beneteau).

We replaced the Volvo with a PSS and it has been problem free for the past 7 years. Somehow I missed that it should be replaced every 6 years so that will be job number one if and when we can get back to Papeete.

We pulled the boat to replace the Volvo seal. Later, a very skilled and knowledgeable marine technician told us two things after the job was done (by someone else). First, we could have just replaced the hose barb and second, we could have done the job with the boat in the water.

Has anybody replaced the PSS bellows without pulling the boat?

That's pretty bizarre, and a plastic hose barb isn't part of the Volvo seal kit - must have been the shaft log itself, which is where the aft end of the seal attaches, and is usually bronze.

I suppose you could pack the shaft exit opening underwater with clay or something else to avoid hauling, but the shaft has to be shoved aft several inches to got the old off and new seal on without damaging the innards.

[mlydon]

To the OP - there’s no nitrile seal - it’s a carbon to stainless face seal. The bellows provides the pressure holding them together......and the bellows are somewhat soft, thin rubber, which is why they need replacing.

I put on a second generation lasdrop on the current boat - uses the same face-seal method, biput uses a heavy hose like a traditional stuffing box, and the carbon face is forced against the stainless face via spring pressure- to my mind a more robust system.....

Matt

[stormalong]

The PSS also has a plastic hose barb. The stator is carbon so a metal fitting would cause electrolysis. PSS will send you a new hose fitting gratis if you call and ask. They also come as straight or right angle fittings.

[jdazey]

Originally Posted by Marathon1150

Has anybody replaced the PSS bellows without pulling the boat?

Yes. You need enough room to move the shaft back and get the coupling off.

[bobmcd625]

I had a PSS seal installed last summer and it was fine at first, but after sitting idle all winter it started to leak after running the engine a month ago. I have tried to reset the bellows but so far it is not working. Going back to the shop as soon as I can.

[Moonflow]

Originally Posted by Marathon1150

Has anybody replaced the PSS bellows without pulling the boat?

Yes. The bellows were cracked so replaced with an old previously used spare from previous owner( 10+ years ago)
The plan was simple however the execution was more complex. Had to undo coupling from gearbox, lift motor, remove coupling from shaft (2 days, ended cutting off with grinder), then replace cracked bellows. Install new coupling, lower motor, align motor/coupling etc.
The faces did not seal so I have a grease line to fill the bellows and tube. Finally no leaks. Working well after 3 hours of motoring. Work in progress. With steel yacht cant allow any drips.

[Journeyman]

Originally Posted by Dave Lochner

I just replaced the seal on my boat after 7 years. It is a small expense to keep the boat above water. Changed over to a split coupling too. The next change will be easier.

When shopping for the new boot, you will notice the sizes are in pairs, like "fits 2" and 2 ⅛" stern tubes. They do this with an insert that can be removed. No mention of this feature is made in the instruction manual nor on the website.

Dave,

Do you have a mfg and part number for that “split coupling”? If by that you mean a clam shell like design that would sure make replacement easier. It seems these concentric seals that require decoupling the shaft are something to be improved on.

Thanks,
Eddie

[bongo]

Originally Posted by stormalong

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 :-).

Stormalong, The Nordic 44’ is a nice ride! I sure would like a Beta/Kubota. But, one thing the 4-108 does well is start when you need it to, so I’ll be living with it. I’m in the yard for bottom maintenance, engine rear seal, PSS, Kiwi Prop new parts/maint, and cutlass bearing. I attempted the rear engine seal once before, in the water. With a V-drive and a PSS that was quite challenging. Bottom line, I swore the next time I attempted it, I’d be on-the-hard, so here I am.

I have a Westerbeke 40-108, Paragon Tranny, & Walter V-drive. Removing the V-drive isn’t that difficult. Removing the Tranny is a PITA, very heavy, situated right under a bulkhead, and has virtually inaccessible hardware. To remove the shaft on my boat you have to remove the V-drive and the propeller. Then slide the shaft forward until it clears the strut, then slide it aft on the Stbd side of the skeg. And on most Valiants the companionway is on the Stbd side, so all lifts have to be improvised. So, if I was doing just the PSS, I’d probably remove the V-drive.

And, yes, I do think I’ll put a secondary collar on it this time. My collar didn’t want to move easily, but it had been there 13 years.

[stormalong]

Originally Posted by bongo

Stormalong, The Nordic 44’ is a nice ride! I sure would like a Beta/Kubota. But, one thing the 4-108 does well is start when you need it to, so I’ll be living with it. I’m in the yard for bottom maintenance, engine rear seal, PSS, Kiwi Prop new parts/maint, and cutlass bearing. I attempted the rear engine seal once before, in the water. With a V-drive and a PSS that was quite challenging. Bottom line, I swore the next time I attempted it, I’d be on-the-hard, so here I am.

I have a Westerbeke 40-108, Paragon Tranny, & Walter V-drive. Removing the V-drive isn’t that difficult. Removing the Tranny is a PITA, very heavy, situated right under a bulkhead, and has virtually inaccessible hardware. To remove the shaft on my boat you have to remove the V-drive and the propeller. Then slide the shaft forward until it clears the strut, then slide it aft on the Stbd side of the skeg. And on most Valiants the companionway is on the Stbd side, so all lifts have to be improvised. So, if I was doing just the PSS, I’d probably remove the V-drive.

And, yes, I do think I’ll put a secondary collar on it this time. My collar didn’t want to move easily, but it had been there 13 years.

Greg, Thanks for the response. I have seen installations as you describe mine is simpler - a Hurth/ZF Marine V drive transmission.

The rear engine seal is what drove me to replace the 4-108. I replaced it once unsuccessfully and determined it required a full overhaul. As the rings wear the crankcase pressure increases from blow by and pushes the oil past the seal. I understand someone is selling an improved seal. Yes, the 4-108 was a great engine. A little under powered for my boat.

I hope the new seal works well for you.

Best, Brian