Leaking Volvo shaft seal

[temptress]

We have a Volvo rubber shaft seal on our prop shaft. this is the sort that you squeeze to purge the air. It is 18months old and had developed a leak.

It is dripping causing the bilge pump to go off every hour or so dumping 4 or 5 ltrs over the side. Tried purging the seal, greasing. This reduced the drip but did not solve the problem.

And suggestions as to what I could do? I can't get lifted out for a few weeks.

 

[Martin_J]

Strange..

It's probably only got about 20mm at the aft end clamped over the stern tube... Could you loosen it and perhaps edge it forwards 3-4mm in order for the two lip seals to seat on a different part of the shaft? I seem to think that little internal lips are about 8mm apart so just sliding a little could ensure they're on clean shaft.

 

[Martin_J]

As a few others have done.. I have managed to replace one of the volvo seals whilst on the water.. but with a 6-8mm gap all the way round between the shaft and the stern tube you do get rather a rush of water.

A good friend with a tea towel does manage to stem the flow sufficiently though..

For future - I had always wondered about putting a spare over the shaft in front of the live seal.. packing the inside to prevent vibration.. but (1) never got round to it and (2) now have saildrive...

 

[temptress]

Martin

Long time good to hear from you. Unfortunately we can't change it in the water. SCOTT and I tried this 18 months ago but there is not enough movement in the shaft. She may have to come out so we can remove the shaft. Other ideas welcome.

 

[RAI]

I had some success by injecting a lot more grease using a grease gun and a flattened plastic straw. Getting the grease into each of the lip chambers helped. Now the shaft doesn't drip when stationary and only very slowly when rotating.

 

[cmedsailor]

. It is 18months old and had developed a leak.

.

Too early to develop a leak. When you eventually change it make sure you check shaft alignment and replace cutlass bearing.

 

[2nd_apprentice]

Just a thought but are your engine mounts ok?

 

[temptress]

The engine mounts were all replaced at the same time as the stern tube. I think something is living in there. . I like the idea with the straw.. Might also try moving the gland a bit though that will have to wait until we are near a lift out facility next week.

 

[mcanderson]

When you fitted the volvo stern seal did you retain the red split plastic that is used during fitting to protect the inner lips? If you did then you might want to consider pushing this into the seal to ensure the inner lips are properly aligned and sealing. I was given this as a tip and it worked!

Here is a link to a photo of the red plastic thingy

http://www.westerly-yachts.co.uk/images/Volvo seal.jpg

 

[temptress]

Mcanderson that's where I started.....

 

[mcanderson]

Sorry, when you said purging I thought you meant squeezing the sides to burb it.

 

[pvb]

It's unusual for them to leak after only 18 months. Is it the correct size? For example, might it be a 1" seal on a 25mm shaft?

 

[l'escargot]

The red plastic piece is just to protect the seal lips when installing the seal over the shaft. If the seal is installed correctly it shouldn't have any use afterwards.

 

[malcp]

I have also had trouble after only 6months of having installed a new Volvo Shaft Seal. This happened 2 years running ('12, '13). In both cases on dismantling the Shaft seal was fine, but the shaft had calcium deposits built up in the area of the lips. I replaced the seal regardless. It seems air had been getting drawn in (despite being burped on launch) and that left a calcium "high tide mark" at the angle of the shaft to the horizontal which caused the seal to leak as it rotated (not when stationary). I have been advised to burp the seal prior to each use and inject more grease several times a season. In the 14 years prior to this I have never had that problem and the seals never leaked (oldest was 7 years). I await Sept/Oct to see if the practice has helped.

To the OP, I think I would try the red plastic piece idea with a view to trying to "scrape" any possible calcium deposits away and push grease further in.

Another cause of the seal leaking is a groove(s) worn on the shaft where the lips make contact, but I guess the leak's most likely when the shaft is rotating.

 

[Albert Ross]

Mine leaked when almost new. Changed it only to find the seal was perfect apart from being distorted by some dried mud in it that was distorting the lips. In retrospect I think it could have been fixed with a a good waggle, squeeze and purge.

 

[temptress]

That seems to be it. I put a load of grease into it and used the plastic thingy to move it around gain. Has reduced the flow to just a few drops. We have a70 mile passage coming up which will likely be motoring a the wind is set to drop. Let's see what the state is at the end of that
Plus side I there is a boatyard there that can has us I needed. fl

 

[Gwylan]

That seems to be it. I put a load of grease into it and used the plastic thingy to move it around gain. Has reduced the flow to just a few drops. We have a70 mile passage coming up which will likely be motoring a the wind is set to drop. Let's see what the state is at the end of that
Plus side I there is a boatyard there that can has us I needed. fl

+1 for the grease up the straw routine = we find the McDonald ones with the sort of spoon end work best. Husqvarna waterproof chain saw grease has been excellent - fraction of the price of the Volvo blue stuff.

We were getting about a litre every time we moved the boat at low speed. Suggestions from the professionals included upping the revs min on the engine! Another insisted that they ought to drip a bit, but that was in Newlyn. Bright lot some of these engineers

Think that the idea of crud in there is good and worth investigating - we are on a mud mooring and it has been much better since we have been in clean water and permanently afloat.

 

[Norman_E]

If you do replace it consider the Eliche Radice seal, which looks and works just like the Volvo one, and is made in the same sizes, but has a greasing point and a water feed point. It is not necessary to feed it with water, just take an open ended tube from the water point up to well above the waterline so that air escapes when you launch the boat. No need to burp it, and its easy to top up the grease. I put one in over winter 2012 and have never had a single drip from it.

 

[l'escargot]

...Think that the idea of crud in there is good and worth investigating - we are on a mud mooring and it has been much better since we have been in clean water and permanently afloat.

I think that is a significant issue in some cases - I was advised against replacing an old style stuffing box with a Volvo seal some years ago when I kept a boat on a drying mud berth.