Redwood

This would be my flapper of choice in this application.
Make sure you cut off the ring and just use the hooks for the installation...

Korky Brand Toilet Tank Repair Products

CNC_guy

^ That's what I installed with the ring cut off and using only the hooks.

Speedbump

I had a similar problem years ago. It about drove me nuts. I finally changed the overflow seat thingie and that fixed the problem. Apparently there was a small crack that I couldn't see that allowed the tank to slowly leak down.

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FAQ's

Redwood

Then go ahead with the flush valve replacement.
Sounds like you have your bases covered.

CNC_guy

Thanks for the replies. I try that next.

CNC_guy

Well, I replaced the flush valve and the leak problem is fixed.

I still have a dripping sound though. After the commode is flushed, you can hear the water running out of the drain very well. It's just like I'm standing there pouring water straight down an open pipe. The commode completes filling and the water shuts off then it makes loud dripping sounds like the water is equaling out between the tank and bowl or something. Then after about a minute it all stops. Again, there is no visible water anywhere and no sewer smell. Also, I can turn the water off for an extended time an no water leaks from the tank.

These sounds were definitely not there before and are not coming from any other commodes in the house. Any ideas or am I being to paranoid about this?