I'm looking for any thoughts or guidance on this as I am officially out of patience:) Here's what I have done, step by step (sorry, this is long...):
Our toilet was running a bit, so we replaced the very old fill valve. All was great, but occasionally we were having some issues with the flapper chain getting caught up and causing the toilet to run A LOT, so I thought I would also replace the flush valve since that part was also really old. I bought an all-in-one repair kit (which for the record claimed to be a simple installation, and was most definitely not:) The all in one kit had a new fill valve, new flush valve, flapper, gasket, etc. The whole rig.
When I removed the tank and replaced everything, the new kit came with a single round rubber gasket, but the gasket that I removed from the old flush valve was a different style- it had three rubber 'stoppers' that inserted into the bolt holes for the tank in addition to the gasket that went around the flush valve. Since the kit said it was 'universal', I didn't think it would matter and installed everything as per the instructions. Once I did that, the toilet leaked horribly out of the bolt holes onto the floor. After trying everything, I found out that our toilet being a Kohler meant that it should have had the same style gasket with the rubber stoppers inserted into the bolt holes. So I went and bought a replacement Kohler gasket, removed the tank (again), installed the new gasket onto the flush valve that came in the universal kit (which meant that I had to use the lock nut that came with the universal kit, not the one that came with the Kohler gasket b/c that didn't fit the shaft of the flush valve), used the new bolts/washers, reattached the tank, cut on the water and YES- no more leaking on the floor.
But, now the tank fills to the correct level, runs water into the bowl until it hits the refill level, and fills. CONSTANTLY. I've checked the overflow pipe, and it's not so low that the water level is above it. I also tried replacing the fill valve with the previous one we had that was new a couple months ago, and it's doing the same thing. I don't think it's a flapper issue because when I push down on the flapper it still runs.
SO... is it possible that using the rubber gasket that didn't come with the kit is causing it to run? It's definitely not leaking onto the floor, just into my tank. Is there anything else I can try? I've spent 2 days and about 6 hours trying to fix this thing, and I'm on the verge of just buying a new toilet, but I really don't want to let this thing defeat me...