PSS shaft seal - experiences?

[Birdseye]

My propellor shaft has worn a bit where the current volvo shaft seal runs on the surface and one alternative to replacing the shaft itself is to replace the volvo shaft seal with a PSS one. Before I sign on the dotted line, what are forum members experiences of this seal?

And are there any other seals which will get me round the issue of the annular groove the Volvo one has worn in the current shaft? For example by running a thin tube over the shaft where its worn and the seal running on that tube.

 

[earlybird]

My boat had a PSS seal when I purchased her in 2004, and probably a few years older than that. No functional problems to date, touch wood!
I've just replaced the bellows as a precaution, ~£60. When dismantled, I could see that the sealing face of the ss rotor had developed a slight pit at one point, so I've turned it round to use the "new" face.

 

[doug748]

I have had one for 5 or six seasons, it has been grand but they are expensive.

Remember that a new shaft is only about a hundred quid, though you must go to a general engineering firm to get this sort of deal.

 

[charles_reed]

My propellor shaft has worn a bit where the current volvo shaft seal runs on the surface and one alternative to replacing the shaft itself is to replace the volvo shaft seal with a PSS one. Before I sign on the dotted line, what are forum members experiences of this seal?

And are there any other seals which will get me round the issue of the annular groove the Volvo one has worn in the current shaft? For example by running a thin tube over the shaft where its worn and the seal running on that tube.

I've had a PSS seal for about 18 years and, apart from the SS rotor being moved down the shaft when the prop is forced out by a wrap, it has been trouble-free.
The SS rotor, which is grub-screwed onto the shaft, has a pair of O-rings which will take up about 0.03mm of of shaft diameter variance. If yours is much more than this you may have sealing problems if the rotor is positioned where the Volvo seal has worn your shaft,
Do check that you get the correct size for your shaft - PSS, being an American firm, use imperial measurement and a 1" seal on a 25mm shaft will leak. They do provide a full range of metric size seals, but the Allen screws are very definitely imperial and it can be a challenge to tighten the screws if you lose the Allen key they provide.
I have dealt direct with them in the States and found them extremely supportive and inexpensive.
I would avoid, like the plague, any botch - it's not that expensive to have a new prop-shaft made - so check the wear at the cutless as this can be significant and would totally justify replacing the shaft. My 1220mm x 25mm shaft cost me €83 to replace in Sevilla 10 years ago, very little more than rebuilding and remachining. I guess that UK prices would be far more expensive.

 

[Houleaux]

An alternative to a PSS seal that might work for you is this: http://www.tidesmarine.co.uk/products/propeller-shaft-seals-seriesone

The seal bears on a different part of the shaft, so wear in the vicinity of the Volvo lip seal won't be a problem.

I've nothing against PSS seals by the way!

 

[vyv_cox]

My PSS has been fitted for about 5-6 years with almost no trouble. After one winter I found the stainless steel seal face to be badly pitted, possibly because I had not flushed it before leaving the boat, although I don't know that for certain. Another forum member contacted me with the same problem. I reversed the seal and have flushed it after each season, since when no trouble. I bought a spare just in case but it remains in its wrapping paper.

 

[RivalRedwing]

Out of interest: how long has the Volvo been in place?

And a quick thought - scoring by the Volvo only puts two narrow bands on the shaft - can you move the shaft forwards or backwards slightly or for that matter relocate the Volvo slightly to avoid the scoring marks?

 

[agurney]

My propellor shaft has worn a bit where the current volvo shaft seal runs on the surface and one alternative to replacing the shaft itself is to replace the volvo shaft seal with a PSS one. Before I sign on the dotted line, what are forum members experiences of this seal?

I fitted a PSS seal myself at the beginning of last season, and have had no problems or drips. Fitting was straightforward; I used a jubilee clip around the shaft as a belt and braces measure to hold the collar in place in case it decided to slip.

 

[macd]

I used a jubilee clip around the shaft as a belt and braces measure to hold the collar in place in case it decided to slip.

Ditto, although there doesn't seem any propensity to slip unless some dipstick forgets to tighten the pinchbolts
I've had a PSS for eight years with no problems apart from that one self-inflicted one. Fit and forget apart from the odd look-see for security's sake.

Birdseye: if you're contemplating buying from ASAP, I believe they now only stock the self-burping version (with a fitting for breather pipe to be led somewhere well above water level, such as a cockpit locker). This is the one to go for.

 

[[2574]]

Vyv,

For interest - I've recently discovered bad corrosion on my boat where an old rubber Halyard seal was affixed to the (316 SS) stern tube. I asked a surveyor to take a look at this (because there was talk of needing to replace the tube as it was diagnosed as electrolytic action by the engineer) and he reported SS corrosion consequent of oxygen starvation where the rubber seal was clamped to the tube. Hence (as not electrolysis and therefore no damage further along the tube in the hull section) I could cut off the badly corroded section and fit the seal on undamaged tube. Maybe that could be the issue which you've experienced?

rob

 

[mickbond]

THis sleeve product might help

http://www.skf.com/uk/products/seal...als/wear-sleeves/skf-speedi-sleeve/index.html

 

[maej]

I fitted a PSS seal myself at the beginning of last season, and have had no problems or drips. Fitting was straightforward; I used a jubilee clip around the shaft as a belt and braces measure to hold the collar in place in case it decided to slip.

Same with me, no problems either (touching wood).

 

[uxb]

I've just fitted a new PSS onto a new shaft and it was easy-peasy.

I was a bit concerned when I saw that all that was keeping me afloat was a carbon bush running on a stainless steel face but the boat is still floating and it doesn't leak a drop when running. Download their tech spec for the seal size you require and see if it will fit with the scored prop shaft you have. You can order a mix of metric and imperial parts to suit your needs.

 

[rgarside]

Fitted a PSS seal 2 seasons ago to replace unsatisfactory Deep Sea Seal. The PSS has performed well and I'm happy with it.

 

[robbieg]

I have had one for 7 years now-as others have said easy to fit and doesn't leak. I think it much better than the Deep Sea Seal I had before. The only point to note is that salt in the thin film of sea water between the s/s collar and carbon rotor can dry out and stick the s/s collar to the carbon face if left for a few days. The vibration of starting the engine normally brakes this "seal" before you put the shaft in gear but if it doesn't the bellows can be twisted until the torsion brakes the seal the salt creates. Personally I don't like the bellows being twisted in this way and since mine is easily accessible so I normally free mine off by hand if I have left the boat for a few days.

 

[chewi]

I fitted a PSS seal myself at the beginning of last season, and have had no problems or drips. Fitting was straightforward; I used a jubilee clip around the shaft as a belt and braces measure to hold the collar in place in case it decided to slip.

+1

 

[john_morris_uk]

We fitted one to our current boat seven years ago and its worked faultlessly ever since. We also fitted one to our previous boat without any problems.

I am sure that the Volvo seal and other seals might be just as good, but I can only comment on the PSS seal that we have used. Its been a very good bit of kit that we are very happy about.

 

[snooks]

Fit it, after 20 odd hours wipe away the carbon splatter marks as the carbon beds in, then forget about it.

 

[[2574]]

MickBond

Thank you very much for that; indeed I think it could well be a useful alternative fix.

Rob

 

[charles_reed]

I fitted a PSS seal myself at the beginning of last season, and have had no problems or drips. Fitting was straightforward; I used a jubilee clip around the shaft as a belt and braces measure to hold the collar in place in case it decided to slip.

Unfortunately a jubilee clip has no apparent effect - if it's going to move it does.
The problem does lie in having a soft connection between prop-shaft and gearbox - that is intended to slip, rather than damage the gearbox and the whole assembly is forced out when you get a wrap.
To indicate the level of forces it quite easily shears an 8mm 316 bolt through shaft and coupling.
Under normal service the grub-screws are quite man enough to hold the rotor in place. I am talking about >4500 hrs of use.
PSS do recommend "burping" the unit after re-launch but, in the 18 years I've had the seal it's never "jammed" and caused any torsion on the bellows. I suspect the compression on the bellows is too great - PSS give tolerances in their fitting instructions and, when I replaced the original bellows after 15 years there were no visual signs of entropy.