Change a Dripless Shaft Seal while in the Water?

[carstenb]

Originally Posted by cram

Apologies, can't delete.... my browser was only showing page 1 and not 2/3..... great work! I feel a little more comfortable doing mine, although I might use a tidal grid (which turns into a 16 hr day.....)

It was less of a problem than i feared. But- makesure you have planned every step and make sure you have laid out every tool you will need

One unexpected issue was that after i removed the coupling i could not push the shaft back. I thought perhaps it was a zinc hitting the cutlass bearing strut. Turned out it was brnacles on the shaft. I had to dive and clean the shaft. Then itslid backwards without an issue

[s/v Jedi]

Originally Posted by carstenb

It was less of a problem than i feared. But- makesure you have planned every step and make sure you have laid out every tool you will need

One unexpected issue was that after i removed the coupling i could not push the shaft back. I thought perhaps it was a zinc hitting the cutlass bearing strut. Turned out it was brnacles on the shaft. I had to dive and clean the shaft. Then itslid backwards without an issue

I can’t watch the video (on a ship eight now…) … did you apply the bubble wrap from the inside or underwater? When you slide the shaft back and forth, did it stay in place?

[carstenb]

Originally Posted by s/v Jedi

I can’t watch the video (on a ship eight now…) … did you apply the bubble wrap from the inside or underwater? When you slide the shaft back and forth, did it stay in place?

I dove under the boat and stuffed from the outside

I slid the shaft bak before stuffing the bubble in. When i had the new seal on. I dove and removed the bubble. Then i slid the shaft forward

[senormechanico]

Originally Posted by carstenb

Mark

Volvo expressly says to grease the seal. Indeed the instructions say to regrease every couple of hundred hours.

I don’t claim to knowmuch about interaction of grease and rubber ( is it npr or some other type of rubber?). But if volvo says grease then i guess it it better to grease

Did Volvo specify what kind of grease? Silicon or oil base?

It might just be a way to keep customers buying more seals.
Job security for Volvo.

[stuartb]

I've done it twice over the years, last time only two years ago ( I forgot it before launch and it started p-ing in a week later )
Mine is difficult access, head first down a hatch in the cockpit sole, max arm's reach.
Mine is a split type coupling so comes off OK.
Get everything ready, slide the shaft back just enough, most boats have enough space before it hits the rudder.

Volvo seal.
25mm shaft.
Maybe 5 litres of water came in while I did it.
To make sure the seal is nicely seated on the tube I used an action cam on a stick. Very clear picture on your phone that way.
Have fun !

[El Pinguino]

Originally Posted by senormechanico

Did Volvo specify what kind of grease? Silicon or oil base?

It might just be a way to keep customers buying more seals.
Job security for Volvo.

Volvo provide a little tube of 'lube' with each new seal. Not sure what it is but it isn't bog standard 'grease'.

Other issue is remembering to 'burp' it when splashing your boat after time on the hard so that it stays water lubricated.

[senormechanico]

Originally Posted by El Pinguino

Volvo provide a little tube of 'lube' with each new seal. Not sure what it is but it isn't bog standard 'grease'.

Other issue is remembering to 'burp' it when splashing your boat after time on the hard so that it stays water lubricated.

Good to hear they do that.

[CaptainMarkS]

Originally Posted by El Pinguino

Volvo provide a little tube of 'lube' with each new seal. Not sure what it is but it isn't bog standard 'grease'.

Other issue is remembering to 'burp' it when splashing your boat after time on the hard so that it stays water lubricated.

Yes, those sachets from Volvo are glycerine, which is non-petroluem based. Petroleum based greases, including vaseline, should never be used with rubber components.

[Pete7]

Originally Posted by senormechanico

Did Volvo specify what kind of grease? Silicon or oil base?

It might just be a way to keep customers buying more seals.
Job security for Volvo.

Running short of VP blue grease, I tried a tube of white Castrol grease I had on board. Within a week of use the seal was leaking but when motoring. When speaking with an old Shipwright and telling him of my problem whilst showing him the seal, he spotted the problem straight away, wrong grease. Cleaned it all out of the seal, refitted with a sugar cube of VP grease and it stopped leaking. Whilst its not cheap, the time taken to fix it again if it leaks means I now use the genuine stuff.

Pete

[rgleason]

I would like to know why cruisers are changing from a heavily built stern tube with many many layers of rubber which hardly ever fails even after 12 years, to a thin rubber bellows on a "dripless shaft seal" which seems to fail frequently and at the most inopportune times. If I had such an emergency failure it would not be at all easy to fix in the best of situations, let alone on the high seas.


I can barely get over the top of the engine, fortunately I have both arms available, but restricted, and I can reach the shaft. My bone structure is compressed by the engine in certain places and if I were claustrophobic I wouldn't be able to do this. It is uncomfortable for long periods and it takes a little while to get into position. It would be impossible with a hot engine.


There must be some reason for people switching to this "dripless shaft seal" is it just that it does not need adjustment from time to time?

I am in the middle of changing my shaft bearing. Just put it in the freezer overnight and then forced it in with 3/8" threaded rod and lots of big washers and two 3/8" couplings (1.5") long for nuts. Now the next decision is to keep what I have for a stuffing box (it still looks pretty good) or go purchase a PSS for $320. Now there should be a damn good reason if I am going to part with that money. Which one is safer? Which one is less prone to catastrophic failure? Which one is easier to fix?

I also expect that a brand new multilayer rubber 5" x 2" stern hose is going to cost a whole lot less if I need it and it would be available almost everywhere. I could clean up the stuffing box theads and redo with teflon again, and that lanacote keeps it nice and clean but sticky.

I guess I just talked my way out of a new PSS.


BTW I did put a PSS on my rudder shaft, but that is a different situation

[Don C L]

Originally Posted by carstenb

I dove under the boat and stuffed from the outside

I slid the shaft bak before stuffing the bubble in. When i had the new seal on. I dove and removed the bubble. Then i slid the shaft forward

Carsten, I am guessing that a big dollop of toilet ring wax would also have worked in this situation?

[carstenb]

Originally Posted by Don C L

Carsten, I am guessing that a big dollop of toilet ring wax would also have worked in this situation?

Probably. But tje bubble wrap was easier to remove

[Statistical]

Originally Posted by rgleason

There must be some reason for people switching to this "dripless shaft seal" is it just that it does not need adjustment from time to time?

That is it. It doesn't drip. It doesn't need adjustment.

[rgleason]

Originally Posted by Statistical

That is it. It doesn't drip. It doesn't need adjustment.

Thank you Statistical for your answer. Do you have any idea how long the thinner and more fragile bellows fails and what causes the failure generally?


How likely is it that the bellows would last 10 years? The information PSS has states 6 years maximum which would be a PITA to change that frequently.

[markxengineerin]

The damned thing leaked just as much when we were under sail as under engine - so the only thing we could do was march on as fast as we could.

Been there, had same experience, although in the USA. Glad it worked out for you!