Volvo "Dripless" Drippy Stern gland....Replacement time

macd said:
It shows no such thing. It merely shows a spigot marked "water". And the seal in the drawing is patently not the RMTA one under discussion, anyway, but concerns "Shaft Logs with flexi inboard gland". On low-speed craft there is no flow through the RMTA's "water" spigot beyond the water in the seal and sterntube finding its own level and by doing so obviating the need for 'burping'. There is no need for a seacock to be associated with it, just as is the case with an equivalent Volvo seal.

I am familiar with the Radice RMTA seal.
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Not quite as straightforward as that. When Beneteau use the Volvo seal they do use a positive water feed from a seacock. As I explained above they do this, particularly on the smaller Oceanis designs because they use a plain composite bearing at the outer end of the stern tube and waterflow forwards is apparently limited. Hence the positive feed. This is achieved by injecting the water into the inboard end of the stern tube just aft of the seal. This ensure than the fluted bearing always has water in it.
 
I fitted a Radice seal a couple of years ago after I discovered the Volvo seal I had fitted earlier was leaking when the engine was running. As we were about to go on our summer cruise in a week I arranged to have the boat lifted and in the cradle over a weekend as I wasn't sure how easy it would be to replace the Volvo seal. It was actually easy and I had completed the replacement in a morning. I led the vent tube high up into a locker. However when I inspected the old Volvo seal, I had obviously fitted it badly as all the sealing lips had inverted! And it still lasted 9yrs.
 
FulmarJeddo said:
If you have a rope cutter, make sure you line it up when you push the shaft back in and tighten the coupling bolts. Otherwise you have to undo it all again. Guess what I didn't check!
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Usually much easier to split the cutter and reassemble than undo the shaft again. Gives you a chance to check the bearings at the same time.
 
MagicalArmchair said:
So coming back across the Thames on Tuesday, I didn't like to tell my new, nervous to sailing pal that we were taking on water as we chugged across the calm glassy waters, so I made him a bacon sandwich, a cup of coffee and surreptitiously pumped the bilges again.

My Volvo dripless shaft seal has been in for err, around seven years I suppose. Its lasted less time than I had hoped, but more time that it specifies on the box, and we've done quite a lot of chugging over those seven years. So, the time has come to replace it. My late father did it last time around, and I must say I didn't pay nearly enough attention (oblique, none). The process, as I see it, is:

  • Lift out (I need to lift out for a scrub anyway).
  • Undo the shaft coupling (mine looks like the "confusing coupling" in Vyvs post here http://coxeng.co.uk/stern-gear/coupling-types-and-removal/) and little grub screw.
  • Pull out shaft until the shaft seal can be removed and replaced.
  • Replace with a Radice? (hurrah, no more burping) Lead a pipe from the Radice up above the waterline/top of cockpit lockers.
  • Lead the shaft back to the coupling. Apply blue locktite to the four main clamp-bolts. Tighten back up (any idea what torque?)
Questions
  • What torque do you tighten the clamp-bolts back up to?
  • Once the clamp-bolts are released, do I need to use a screwdriver or the like to splay the clamp to release the shaft? Or with this sort of shaft the way that Vyv suggests here is the best bet?
  • Is a Radice still a good bet these days? Not superseded by anything?
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Ha, so finally getting around to this job. When undoing the coupling, what is usually in the below, circled in Red. Is it a roll pin? I seem to remember it being another grub screw when my father did this operation for me last time around? If it is a roll pin, is it just a case of driving it through?

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Picture taken from Vyvs site here: http://coxeng.co.uk/stern-gear/coupling-types-and-removal/
 
I'm sure mine has a nut and bolt through it.

Edit. I began to think I was going mad looking at that image, so googled shaft coupling and came up with Viv's page. https://coxengineering.sharepoint.com/Pages/Couplings.aspx Mine is a Volvo 2002 and there is an example, but the image you have used is one with a sheared grub screw. There's another image showing a coupling with the grub screw complete.
 
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MagicalArmchair said:
Ha, so finally getting around to this job. When undoing the coupling, what is usually in the below, circled in Red. Is it a roll pin? I seem to remember it being another grub screw when my father did this operation for me last time around? If it is a roll pin, is it just a case of driving it through?

Picture taken from Vyvs site here: http://coxeng.co.uk/stern-gear/coupling-types-and-removal/
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+ can be two grub screws one on top of the other
 
On my boat its a pointed screw into a deep dimple in the shaft, and there is a locknut to stop it unscrewing.

As for the OP having a Volvo seal leaking badly after only seven years, either it was not burped and ran too hot, or the shaft is damaged and has ruined the seal. If the latter the new seal will also fail.
 
Norman_E said:
On my boat its a pointed screw into a deep dimple in the shaft, and there is a locknut to stop it unscrewing.

As for the OP having a Volvo seal leaking badly after only seven years, either it was not burped and ran too hot, or the shaft is damaged and has ruined the seal. If the latter the new seal will also fail.
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Thanks all. I seem to remember the shaft had some crevice corrosion on the shaft at the point the seal went over it, it didn't have any burrs mind you. When I remove the seal at the weekend, I'll take it home and saw it in half to see why it failed and take some photos of the shaft.
 
So, I did this job at the weekend, and, guess what, the seal was absolutely fine. The clamp on the stern tube had come loose and when the shaft was turning, that was enough to start a little dribble coming through. Look at the back of the removed VP seal, you can see where water has been coming in:

fnD4EbAl.jpg


Still, at least no more burping required!

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If anyone wants a free VP shaftseal with another ten years of life in it gratis, let me know!
 
Good job done I think.

Did your stern tube have a lip on? I thought they all did, but when I stripped mine the tube was smaller than I expected. It meant an anxious sikaflex repair, which fortunately set sufficiently before the tide came in, and allowed me to get back to my berth.

Mike
 
The tube is rather tiny to be fair, however, I never had a problem with the VP seal on it... other than it finally rattling itself loose.

Here is a picture of Triolas stern tube during the strip down. Note the wear on the shaft is from the old oil fed seal I think.

RhBQubSl.jpg
 
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