Re: Send packing the stuffing gland..
The only o-rings in my PSS shaft seal are on the rotor, which is fixed to the shaft. There isn't any maintenance that I feel is necessary here. You could check with PYI to get there opinion on routine maintenance.
I replaced my bellows when they were about 18 years old. They seemed stiff to me, but there weren't any drips, so it was purely precautionary. PYI advised me that this was the right approach. The newer bellows use a different material.
My dripless shaft seal has performed flawlessly for 22 years. I do not have the tube for water lubrication, which makes more sense on a power boat running longer and at higher revs. My seal gets lubricated by whatever water gets thru the cutless bearing.
I've wondered about a catastrophic failure but, should the seal or bellows blow out, it seems highly unlikely that enough water would flow past the cutless bearing to overwhelm a bilge pump. I'm fairly certain I could keep up with it using the manual backup bilge pump in my cockpit.