PSS Shaft Seal problems

[McGeorge]

Has anyone experience of problems with a PSS Shaft Seal? I have had the boat for just a year and until July, barely a dribble of water had entered through the shaft seal. But after a few weeks of no activity, suddenly we have leakage! The vibration of the shaft seems to be more than it copes with! Under power, I have to pump the bilge every 20 minutes or so!
I have not yet been able to check the compression on the bellows yet (still in the water), but will try this when ashore in a few weeks.
Any experiences in this area would be helpful, thank you.

 

[boatbuilder]

If you look on PSS website you will see the dimension for the compressed bellows, depending on shaft size. A quick measure of yours will let you know if ths grub screw has come undone and the bellows moved.
You can then just re compress and make sure the grub screw realy bites.

Obviosly you have checked all the jubilee clips.

 

[alan17]

PSS Shaft seal

When I fitted mine I used 2 jubilee clips on the shaft to make sure that the bellows remained as fitted. I did increase pressure once and this was made easier by the jublee clips. Simply slacken the one nearest the bellows slacken the bellows clip push bellows towards stern tube and secure. Move slackened jubilee clip upto bellows and resecure. The gap between the two clips on the shaft clearly indicates the increase in pressure. Finally move the clip furthest from the stern tube upto the other clip and retighten.

 

[Barry Jones]

Do you have a shaft coupling like a Aquadrive or similar ??

 

[Tranona]

Probably the bellows, although vibration could mean the sealing faces are damaged. Do the easy bit first and check the bellows compression.

 

[30boat]

Do yourself a favour and replace it with a Volvo seal at the nearest opportunity.I had three PSS seals and all gave trouble.In the meantime check compression of the bellows as said.The faces can wear and leak and no adjustment can cure that.

 

[vyv_cox]

But after a few weeks of no activity, suddenly we have leakage!

Does this mean that the boat was unused during the inactive period? The PSS instructions advise that the seal face should be wetted before starting after remaining stationary for a month or more.

 

[McGeorge]

Thanks

Thanks to all for your input. The inactive period was not as long as a month..perhaps 2-3 weeks as I remember. As you say, the easy bit is checking /increasing the compression a bit, but I didn't fancy trying that while in the water! Coming out soon.
I'll look into Volvo seals in case this problem is terminal!

 

[DickB]

Thanks to all for your input. The inactive period was not as long as a month..perhaps 2-3 weeks as I remember. As you say, the easy bit is checking /increasing the compression a bit, but I didn't fancy trying that while in the water! Coming out soon.
I'll look into Volvo seals in case this problem is terminal!

Only time I had a problem was when the SS disc crept along the drive shaft and a trickle of water started. Pushed it back against the bellows and tightened up the grub screws. No problems since!!!

 

[Robin]

Unless the seal is ancient it is probably only the compression adjustment that has slipped and personally I would want to do this afloat to see if it effects a cure. If you wait until ashore, adjust then re-launch but find it still drips then you have another lift out to replace it. I'm assuming it is a genuine PSS seal not a Deep Sea Seal (the horrible one with a clamp for emergency sealing), because the S/S shaft mounted seal face of the PSS is very well designed to give a sturdy face at exactly 90 degs to the shaft, something hard to achieve on others, like the Deep Sea for example. The PSS IIRC (sold our boat now with it) S/S collar clamp has grub screws to tighten onto the shaft to hold the collar in place, but I added a jubilee clip behind ours as a backup, having had a near disaster with a crap slipped Deep Sea Seal in the past. Ours had an air bleed tube taken above the waterline too that eliminated any problems of lack of use or drying out, the same tube could be used on fast boats for water injection. This version with the bleed or water injection is the only one I think sold now by the UK agents.

 

[john_morris_uk]

Do yourself a favour and replace it with a Volvo seal at the nearest opportunity.I had three PSS seals and all gave trouble.In the meantime check compression of the bellows as said.The faces can wear and leak and no adjustment can cure that.

Nothing like a firm opinion to sway peoples perceptions?

By way of balance, we have fitted PSS seals to our last two boats and never had a problem. On our current boat the PSS seal replaced a very dodgy Volvo seal.

Now the truth is (I think) that both seals are fine so long as they are fitted and maintained correctly. eg The Volvo seal had failed because the engine mounts had failed putting the shaft severely out of line.

To the OP, there is no problem with adjusting the PSS seal whilst the boat is in the water. In fact, you can occasionally flex the bellows a bit and pull the carbon compound block away from the collar on the shaft to allow a little water in to lubricate it when it is set up properly.

As others have said, check that the parts aren't cracked or damaged, and then adjust the position of the collar. Our collar is held with two pairs of grub screws (allen key type) You have to remove the one grub screw completely in oder to slacken the one underneath to adjust the collar. I wouldn't want you to slacken the first (top) grub screw and wonder why the collar was still stuck. Its not that easy to move on the shaft as its got an 'O' ring between the collar and the shaft.

(Perhaps the 'O' ring has split?) Where is the leak coming from?

In my experience PSS seals are pretty much fit and forget and ours never leaks. (It squeaks a bit sometimes but that's another story...)

 

[Robin]

Nothing like a firm opinion to sway peoples perceptions?

By way of balance, we have fitted PSS seals to our last two boats and never had a problem. On our current boat the PSS seal replaced a very dodgy Volvo seal.

Now the truth is (I think) that both seals are fine so long as they are fitted and maintained correctly. eg The Volvo seal had failed because the engine mounts had failed putting the shaft severely out of line.

To the OP, there is no problem with adjusting the PSS seal whilst the boat is in the water. In fact, you can occasionally flex the bellows a bit and pull the carbon compound block away from the collar on the shaft to allow a little water in to lubricate it when it is set up properly.

As others have said, check that the parts aren't cracked or damaged, and then adjust the position of the collar. Our collar is held with two pairs of grub screws (allen key type) You have to remove the one grub screw completely in oder to slacken the one underneath to adjust the collar. I wouldn't want you to slacken the first (top) grub screw and wonder why the collar was still stuck. Its not that easy to move on the shaft as its got an 'O' ring between the collar and the shaft.

(Perhaps the 'O' ring has split?) Where is the leak coming from?

In my experience PSS seals are pretty much fit and forget and ours never leaks. (It squeaks a bit sometimes but that's another story...)

Hear hear!

I think BTW there are two 'O' rings in the PSS S/S collar, as one alone would allow it to sit wonky and not square to the shaft. Since the collar is fixed and does not rotate on the shaft only with the shaft, there is no wear on the 'O' rings and they are unlikely ever to cause a leak. One major advantage of this design is that the seal will work with a shaft that has been worn locally by a conventional stuffing box type maybe being over tightened as lots of them are.

 

[tidclacy]

Had a similar problem in the summer coming out of Ouistreham lock in the summer. Water was pouring in. Managed to tighten and had no problems since. But how do you measure the compression needed on the Bellows. I also don't seem to have the locking grub screws, any idea where I might get them?

 

[30boat]

Nothing like a firm opinion to sway peoples perceptions?

By way of balance, we have fitted PSS seals to our last two boats and never had a problem. On our current boat the PSS seal replaced a very dodgy Volvo seal.

Now the truth is (I think) that both seals are fine so long as they are fitted and maintained correctly. eg The Volvo seal had failed because the engine mounts had failed putting the shaft severely out of line.

To the OP, there is no problem with adjusting the PSS seal whilst the boat is in the water. In fact, you can occasionally flex the bellows a bit and pull the carbon compound block away from the collar on the shaft to allow a little water in to lubricate it when it is set up properly.

As others have said, check that the parts aren't cracked or damaged, and then adjust the position of the collar. Our collar is held with two pairs of grub screws (allen key type) You have to remove the one grub screw completely in oder to slacken the one underneath to adjust the collar. I wouldn't want you to slacken the first (top) grub screw and wonder why the collar was still stuck. Its not that easy to move on the shaft as its got an 'O' ring between the collar and the shaft.

(Perhaps the 'O' ring has split?) Where is the leak coming from?

In my experience PSS seals are pretty much fit and forget and ours never leaks. (It squeaks a bit sometimes but that's another story...)

My bad,I confused the PSS with the Deep Sea Seal which is in effect a terrible product,sorry.I still consider the Volvo seal a much better solution though.

 

[boatbuilder]

Had a similar problem in the summer coming out of Ouistreham lock in the summer. Water was pouring in. Managed to tighten and had no problems since. But how do you measure the compression needed on the Bellows. I also don't seem to have the locking grub screws, any idea where I might get them?

Well if you dont have them you dont have PSS, as it is the grub screws that hold the shaft piece in place.
Or they have fallen out, however I can't see how it would work without them.

You could have a Deepsea seal, a wholly different animal.

 

[john_morris_uk]

Well if you dont have them you dont have PSS, as it is the grub screws that hold the shaft piece in place.
Or they have fallen out, however I can't see how it would work without them.

You could have a Deepsea seal, a wholly different animal.

If you mean by locking grub screws that sit over the grub screws that secure the collar to the shaft, I am sure that PSS can supply some. Our seals came with spare screws as they have some anti vibration compound on them.

Robin is right when he says there are two 'O' rings - I should have been more explicit in my description. I suppose its very unlikely that both of them would split and allow a leak between collar and shaft - the collar doesn't rotate on the shaft as its locked in position by the grub screws.

 

[tidclacy]

Yes I do have the PSS seal and its the extra locking screws I am missing. Will try to get spare pair from supplier.

 

[boatbuilder]

Well make sure that you put it in with locktite

 

[vyv_cox]

Yes I do have the PSS seal and its the extra locking screws I am missing. Will try to get spare pair from supplier.

We bought some recently from Aquafax.

 

[contessaman]

Has anyone experience of problems with a PSS Shaft Seal? I have had the boat for just a year and until July, barely a dribble of water had entered through the shaft seal. But after a few weeks of no activity, suddenly we have leakage! The vibration of the shaft seems to be more than it copes with! Under power, I have to pump the bilge every 20 minutes or so!
I have not yet been able to check the compression on the bellows yet (still in the water), but will try this when ashore in a few weeks.
Any experiences in this area would be helpful, thank you.

Just bought a boat with a PSS seal, I have no experience with this system. Looks like it takes a feed of pressurised water form the engine cooling pump.

That leaves me with a question. I winterise my engine in the usual manner, i.e. pulling the cooling hose off the inlet seacock, then sticking it in a bucket of water/antifreeze until the exhaust runs blue.

This technique will presumably pressurise the PSS with said antifreeze mixture. Will that then harm the materials in the unit, when left for 6 months over the winter?

I will be winterising afloat in marina so draining the seal isnt really an option.

thanks in advance!