PSS Shaft Seals

[Robert Mann]

Please excuse me for opening up an old topic, but I need some advice.  I have just returned from a 6 year overseas posting and I am beginning to get my boat operational again.  She was left in fresh water with good bottom maintenance and occasional cleaning.  Engine fired and runs well, no problems there, but I have noticed some leakage from the PSS shaft sealing system when the boat is underway.  There does not seem to be leakage when she is stationary.  Boat is a 2002, and as such a bellows replacement would be in order, but not happening in the next few months, until I can haul out.  Does anyone have any similar experiences with the PSS and any advice on how this type of leakage can be cured?  There seems to be a school of thought that cleans the sealing faces with very fine wet and dry, but this seems a little counter to the operating principle of the system.  Any input appreciated

[John Langford]

You may want to run the engine in gear for awhile to clean up the interface between the carbon graphite flange and stainless steel rotor. In addition with the engine off or in idle you can slip a very light grit piece of wet and dry sandpaper between the two facings and give them a light sanding. Finally, the bellows can get tired after a few years and you may want to try loosening the SS rotor set screws and pushing the rotor aft a bit to compress the bellows. Remember to retighten the set screws on the donut and as an extra precaution put a hose clamp on the shaft tight up against the front of the rotor to ensure that it can't slip forward. There is advice about how tight the connection should be in the installation instructions. See http://www.shaftseal.com/de/about/installation_instructions

[Robert Mann]

Thanks John, I will try putting her in gear in the slip and running for a while.  Also, putting a little more tension on the bellows may help as the installation is 12 years old.  I never liked working on flax packed stuffing boxes and I'm too sure I like these either, a lot of water moving about during maintenance!

[Carolina Soul]

You might try "burping the bellows."  I had a drip when I purchased my boat - and it had been sitting for awhile.  I compressed the bellows and then released it (might take a couple of times), the theory is it will clean out debris that has found it's way into your system.  Worked for me - two years now without a drip.  Bill Mathus.

[Robert Mann]

Well, I started her up in the slip, put it her in ahead at about 1500 rpm while tied to the slip, and not a drip was seen.  I'm wondering if I didn't blow what ever was on the face out when I burped the bellows.  I did get  the engine a little hot though.  Good excuse to replace the raw water impeller, which was not so good.  I must say I would rather replace a Jabsco impeller than the Sherwood, if I was at sea and needed to do so in a hurry.  The whole rear bolt thing is just a little tight on a hot engine.  The Sherwood must have saved Westerbeke some money!

[tonywright]

Two thoughts:
1) You are missing the vented collar: this was and may still be a free upgrade from the company. Avoids getting an air pocket in the bellows, and causing the graphite to overheat.
2) The bellows replacement schedule is every five years. Sounds like you may be overdue. (btw Excellent article by Mainesail on his site re the work to remove and replace the shaft coupling, and mistakes to avoid at all costs).

Tony

[Robert Mann]

Yes this one is a 2002 vintage!  The vented bellows was originally for high speed applications and then moved in the lower speeds I believe.  The bellows are in excellent shape, (133 engine hours) flexible and now leakless.  I will change it next haul out, so I'm not getting too excited about it.  I think it is possible to change one in the water, if the stainless collar is movable on the tranny tail-shaft without a puller, but I'm not that brave, yet.