Shaft Seal Leakage

[Noname]

Offered for information purposes:
PYI sells a maintenance kit for the shaftseal for about $85 for the 1inch shaft and 1.5 inch stern tube, which is what I bought. PSS Shaft Seal
I replaced my 12 year old bellows this past March,during the haulout for bottom job, using the kit. The stainless rotor and carbon had no leaks so I thought they would be perfectly usable, which they were. The old bellows had no leaks and the new installation was well done by the mechanic at the yard and is leak-free.
If you replace the entire shaftseal with the new model, it requires plumbing a water source to the bellows, which I did not want to have done.

[delmarrey]

Originally Posted by Seaduction

If you replace the entire shaftseal with the new model, it requires plumbing a water source to the bellows, which I did not want to have done.

It's not necessarily a water source. It can be plumbed as a vent tube, to allow air to escape w/o burping. It also depends on the amount of water that is able to get to the seal under normal operation (small stern tube clearance), so it doesn't get hot. But should be installed as such for hi-speed props (power boats).

[Noname]

Originally Posted by delmarrey

It's not necessarily a water source. It can be plumbed as a vent tube, to allow air to escape w/o burping. It also depends on the amount of water that is able to get to the seal under normal operation (small stern tube clearance), so it doesn't get hot. But should be installed as such for hi-speed props (power boats).

I didn't realize that. Thank you for the clarification.

[rusky]

I have the same system. It has leaked, so I have had the same 'fun'. It now appears to have re-set and is fine. I did re-tension the bellows. Some of the Allen keys have a smaller Allen 'grub screw' within - look for a 'X' inscribed.

After you clean the 'faces' it will leak again until it has re-set/aligned/ground itself to a new level.

Until mine stopped leaking, I cut up a 1 L water bottle and cable tied it around the bellows. This stopped spray flying around.

[delmarrey]

BTW as an FYI, if ones boat sits on the hard for long periods like mine, while it's out of the water it's best the loosen the set screws and back off the SS ring.

My last unit had sat on the hard for a year with the bellows under pressure. I needed to pull the prop shaft and discovered that the ring had become pitted, probably form the lack of air on the SS ring, and or the constant resealing from rotation.
I machined off .008" from the face and polished it and it was all good again. Also, there are two sides to the rings. PYI uses a 400 series SS. The 316 SS is too soft to last.

[sailorboy1]

The good news - I moved my stationary ring 1/16" and found the leak.

The bads news - it is the rubber bellows and all increasing the tension did was make it leak faster. So only way to fix is to pull the shaft, which means at least a new hub. Turns out these things are suppose to be replaced every 8-10 years so what looks like an inexpensive maintenance item isn't once you take into account all that is involved.

The good news temporary - Rescue tape is wonderful stuff and everyone should have a roll on their boat!

For the time and money involved I'm thinking of just changing over to packing! I can make a sump for the drips and run it to my shower sump so will never have wet bilge!