Review on 💦 Optimized Flush Valve Seat Disc - Fluidmaster 5103 by Reginald Truitt

I had an old (circa 1960's) US Standard F-4049 toilet that needed a valve replacement. I replaced it with this one and while that solved the leak/fill issue somewhat, it still leaks no matter what. I even cleaned the (bottom) surface with mineral spirits to remove any oily residue that might interfere with the tight fit, but to no avail. I then ordered the original spare part elsewhere. It was double the price (shipping included) but now I don't have Phantom refills all the time. YMMV.