A month ago I posted about problems with a leaky flush valve. It was
a brand new fluidmaster flush valve. I changed flappers twice to see
if I could get it to stop. Didn't work. fed up with the noise and
the water waste, I finally took the tank off and replaced it.
When i got the thing at eye level I noticed that the dimension between
the flapper hinge pins and the flapper seat was such that the back of
the flapper sat off the seat a few thousands of an inch. All three
flappers did this, the original and both replacements. So the flush
valve was defective, brand new.
I replaced with a Korky. Blessed silence.
It is still a mystery as to why it would often leak down 2-3" and then
stop (with the fill supply valve closed for testing). I guess I'll
never figure that out.
No more fluidmaster for me.