On my Toto toilet I have replaced the flapper three times in the past three days, using two different style compatible flappers, and also had a plumber be unable to isolate the cause.

The flush value orifice onto which the flapper seats appears to be smooth and sound, and no cracks can be found in either the flush valve or the overflow tube. The leak is almost imperceptible to the ear, but the tank drains completely with the water off in five minutes.

If I hold down the latest flapper (apply pressure), the leak doesn’t occur and when I release, the flapper seems to hold. I have considered weighting the flapper and could also try the Vaseline fix but again, I have my 3rd brand new flapper installed.

I suspect that the upper orifice of the flush valve (into which the flapper seats) is somehow compromised, but no imperfections can be observed by the naked eye, or felt.

I could try replacing both the flush valve and the overflow tube, and I may do so. I may also buy a new toilet, but would prefer not to.

Any other suggestions? I’m confounded!

Does the tank drain down and stop at the flapper or will the tank drain down below the flapper?

??? " compatible flapper " ???


try Toto OEM flapper


BUT


FIRST answer Steve's question - if the ENTIRE tank empties it is NOT a flapper issue

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

steve, he said if he pushes down on the flapper it stops the leak ????
i would think if there was a crack in the flush valve this would not help.

i would contact toto tech help. there may be a design issue ?

Slides all the chips on (Not the proper flapper). A Picture of the inside of the tank would be nice if you could post one.



Edited 1 times.

For many toilets you must get the manufacturers parts, particularly for the flapper.

One thing I have found is that unless the flapper is in a package (not loose in a pile), that they will distort.

I have almost NEVER had that be the case, unless it was a very special design, such as American Standard.

Make sure the chain attached to the flapper has a little slack in it when the flapper is down. Otherwise the flapper is held up and does not make good contact with the opening. I had this problem on my Toto a couple years back.
Bernie

Cracked flush valve

Pressure on the flapper would NOT cause the leak to stop, in that case.

"If I hold down the latest flapper (apply pressure), the leak doesn’t occur and when I release, the flapper seems to hold."

That seems to suggest two possibilities.

(1) The mating surfaces between the flapper and the flush valve inlet is not perfectly sealed when pressure is not applied.

(2) One or both tank to bowl bolts is loose a little bit, and when pressure is applied to the flapper, that same pressure transfers to the bottom of the tank and the bolt washer(s) seal better? If there is a leak in the tank bolt, will it not leak to the top of the bowl, either run to the front down the bowl or down to the floor?

Again, use the manufacturers flapper to solve the problem.