I have a slow leak from my flush valve on a one-piece American Standard toilet. I replaced the disk twice to no avail. Then I replaced the gasket (twice). I even resorted to trying it with the gasket + silicone and the gasket + vaseline. I tightened the 3 screws very tightly with a small wratchet. I have removed and replaced the valve about 20 times, and with the upper part of the valve removed, and a 6x6 sheet of silicone over the lower half of the valve, I still see the water movement and slow leak from tank to bowl.

Thanks

 

Whoa, slow down! Welcome to the forums. You will probably need to undo everything you did, especially with the silicone, and start over. The leaking from the tank to the bowl may be something as simple as the flapper being old and soft, misaligned or the chain too tight. The water line may exceed the overflow tube, or the fill tube may be stuck too far into the overflow tube.
If you haven't cracked the unit yet with the ratchet, you could clean up all the silicone and purchase new flapper/fill valve, etc as a kit and start over.
After checking all the above, post back with the results so we will have another place to start. Good luck.

 

.... change that disc, look inside the ballcock, there is a brass seat. Get an allen wrench of the appropriate size, stick it in that seat, turn it out and replace it. That way you will KNOW its not the ballcock or even easier turn the water off, give some time see if you still have water leaking in the bowl.

 

Shortening the fill tube stopped the constant bowl dripping, but there is still a slight leak from the tank to the bowl (the fill valve opens up for about 10 seconds several times a day). The flapper is new, and I reseated the flush valve with a new gasket. The flush valve itself appears to be in good shape--I think it is cast bronze. There is slack on the flapper chain also.

Thanks,
Doubledang

 

Thank you so much for all your suggestions. Replaced the 3 screws and retaining ears on the flush valve, and that did it. No more hearing that constant topping off of the tank all night.

Thanks again,
Doubledang