"Has anyone found anything of significance when disassembling Gascolator for inspection?"
One RV- found degraded Proseal particles, this plane did not have any inline filter upstream.
Another RV- found significant deposit of brass shavings, this plane had a SDS FI system on it but the electric fuel pumps were another brand & it was chewing its self to pieces. New SDS pumps installed and system lines flushed.
An F-1 Rocket - found white sludge deposit as well significant corrosion of the gascolator bowl, obviously triggered further inspection of other components in the fuel system. Resulted in replacement of fuel lines, selector valve, filter, gascolator, fuel pump, aux fuel pump, AND SERVO! Honestly don't know how that engine could run. I suggested that the tanks should be pulled & power flushed too, but owner didn't agree. Culprit- Ethanol & long term storage.
SuperStol- pretty much the same as the F-1, full system was either steam cleaned or replaced, priced out a Rotax carb (times 2) & fuel pump lately? Culprit- Ethanol & long term storage.
Other RVs & such, found small deposits of whatever, but in our climate rarely found water.
If the gascolator bowl is stubborn coming off, the o-ring might have swollen for some reason, best to replace it before putting it back together. In the case of Andair gascolators, I normally keep spare o-rings on the shelf.