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
source to the bellows, which I did not want to have done.