Volvo shaft seal - will it fit?

MoodySabre

MoodySabre

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today I got the coupling off and the old greaser stern gland so that I can fit a dripless jobbie. I had hoped to use the Volvo one - cheap and very well spoken of BUT Volspec tell me that for a 1" shaft the max stern gland OD is 1 3/4". My stern tube is 1 7/8" with a 2" lip. Are Volspec being cautious or is this really a no no?

The alternative is a Tides Marine shaft seal that cost lots more but is also well recommended.

Any ideas/comments? What it is to know so many experts /forums/images/graemlins/smile.gif
 
No, I don't think Volspec are being cautious. The Volvo seal is a very chunky lump of hard rubber, and there's little chance of stretching it to fit your stern tube - even if you grind off the 2" lip. The Volvo accessory catalogue quotes the 1¾" dimension with a tolerance of +0.5mm, so that indicates how little it stretches.
 
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No, I don't think Volspec are being cautious. The Volvo seal is a very chunky lump of hard rubber, and there's little chance of stretching it to fit your stern tube - even if you grind off the 2" lip. The Volvo accessory catalogue quotes the 1¾" dimension with a tolerance of +0.5mm, so that indicates how little it stretches.

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You may be right, but I wonder if there is sufficient wall thickness on the tube for it to allow grinding down to the 13/4" required. Not sure whether it's a bronze or grp stern tube but taking off 1.5 mm all round might be ok.

Worth looking at I reckon.
 
I had a similar problem when I wanted to fit a Volvo seal - no version to fit my combination of shaft and stern tube sizes. Went for a PSS from ASAP supplies in the end. More expensive, but a good bit of kit which did not let in one drop of water the whole season last year.
 
One thing you can do is to fit the seal to a short S.Steel tube wich in turn is held on to the shaft tube with a length of suitable rubber hose.You may have to have the tube turned by an engineer to the required diameters but this way it should be possible to fit the seal, wich is excelent,by the way.
 
Let us know how you get on?

I am still trying to decide whether to fit a volvo or pss - one is simple, cheaper, with a good rep, but less tolerance; the other has an excellent rep, more complex to fit, but will cope with more variables regarding alignment etc.

Have I got that about right?
 
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Let us know how you get on?

I am still trying to decide whether to fit a volvo or pss - one is simple, cheaper, with a good rep, but less tolerance; the other has an excellent rep, more complex to fit, but will cope with more variables regarding alignment etc.

Have I got that about right?

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Hi Damo,
The Volvo seal is a superb bit of kit at, for Volvo, a very sensible price. With regard to 'less tolerance, I can't agree. The Volvo seal will allow the shaft to move to the limits of the stern tube to which it's fixed without a sign of a leak, and that's some misalignment!!

As you probably know, it achieves this by having what is effectively a 'cutless' type bearing aft of the two seals, which keeps them exactly in line with the shaft if there is a misalignment. The seals are therefore not distorted in any way. At least that's been mine and many of my friends' experience.

I have no connection with Volvo, but this bit of kit really is excellent and virtually maintenance free save for the 'burping' after drying out and the annual squirt of grease, both of which are (or can be) done with the boat afloat.

I may be wrong as I've never used a PSS seal, and can't therefore comment on its ability to cope with the maximum misalignment noted above, but I'd be surprised if it could do it for any length of time before excess wear allowed at least a little seepage.
 
Thanks guys. I'll report back but at the moment I'm looking at this Tides Marine shaft seal which at $194 is cheaper than a PSS. I am told they are fit and forget and totally dripless. I was told that if your shaft is not perfect then the PSS will wear unevenly and start dripping. Maybe that's true of Tides too. The Tides one looks simpler which is an attraction and you can change the seals whilst in the water which might prove a bonus. Probably makes you buy a spare /forums/images/graemlins/ooo.gif
 
I would go for the Volvo Seal. There is almost certainly enough meat in the bronze housing on the inboard end of the stern tube to turn it down to 1 3/4. I had this done on my boat which has a Stuart Turner stern tube. I expect yours is a bronze housing for the stuffing box attached to the tube with a rubber hose, but the same principle applies.

IMO the Volvo seal is superior to the others you are considering as they rely on a face to face contact for a seal rather than a radial seal. Although Volvo suggest you change the seal every 5 years, this is very conservative. Mine has been in place for 10 years and has never leaked a drop except when venting it. You need to grease every year and that is all.
 
<<<< I was told that if your shaft is not perfect then the PSS will wear unevenly and start dripping. >>>

My shaft is in a terrible state, probably the age of the boat, 20 years plus, very worn at the cutless bearing and generally quite badly marked everywhere inside the boat. It will be replaced this spring. However, I fitted my PSS seal last spring and it has performed perfectly. There is clearly a bit of bend in the shaft but the rubber hose copes perfectly well with it. It has not dripped a drop since I installed it. The carbon face doesn't seem to have worn at all unevenly.

Further to a previous comment, it is not in the slightest difficult to fit. Slide the hose and fixed part up the shaft and connect it to the stern tube, push the seal face up until it touches and then push a further 3/4 inch ( dependent upon size ) Could hardly be easier.
 
One thing to be aware of with the PSS seal, and probably also the Tides, although I'm not so familar with this one, is that you cannot move the shaft back and forward with the boat in the water as you would need to do when alligning the engine by checking the gearbox flange/shaft coupling faces with feeler gauges. This is because if you have a flexible coupling between the two, as most people will (eg. R&D type), to get this out/in you need to be able to move the shaft for/aft. This is fine with a conventional gland or the volvo seal, but cannot be done without a flood with the PSS. It is of course recommended that engine allignement is done with the boat in the water, but I have not been able to work out a way to do it so have to be satisfied with the assumption that the hull shape is almost the same whether on the hard or floating. No problems so far! Would be interested to hear if anyone has overcome this problem.
 
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