Spider gasket adhesive question

Does the spider gasket seat in the multiport valve have to be completely dry when replacing the spider gasket with a new one? That is, will the 6B adhesive still adhere sufficiently if water remains in the gasket seat when I stick the gasket in the seat? The reason I ask is because my stop valves don't stop 100% of the water when closed and my multiport valve has not been installed in a removable manner. So a slow trickle of water seeps into the bottom of the valve and keeps the gasket seat wet.

I installed a new spider gasket valve without adhesive (but with plenty of lubricant) at the beginning of the summer and it is already coming unseated. I probably should just replace the multiport valve. The one I have is from the 1970's. But I didn't want to attempt it until after the swimming season is over.

There are a few adhesives that work wet, but most don't. I have no idea what "6B adhesive" is, so I don't know if it works on wet or damp surfaces.

In my personal experience, replacing multiport gaskets always proved to be a fairly short term repair.

What is the alternative to replacing the gasket? Replacing the multiport valve itself?

Yep.

I have limped along for a while, replacing gaskets every 3 - 4 months.