In alt.home.repair, on Fri, 2 Oct 2015 10:13:32 +0630, John Smith
wrote:

Two of my toilets are of the same model. Both are made by American
Standard and both use the flapper as shown in the following link:

http://www.lowes.com/pd_236807-143-P...ductId=3375098

Lowe's sells this flapper for around $9. Here, I need to pay more than
$30 for it.

About three months ago, one flapper would not come down after flushing.
I thoroughly cleaned it and then put it back. It started to leak. I
tried many things but ended up buying a new one.

Now, the other toilet has the exact same problem. Yesterday, I was

Flappers seem to wear out consistently, in the same amount of time, so
if one wears out, one the same age might not be far behind.

informed that the flapper would not come down. I went to check it. It
was not leaking at that time. I removed the flapper and cleaned it.
After I put it back, it started to leak, just like the other one. I used
a toothbrush and a plastic brush to clean. They should not damage the
flapper.

Can anyone explain why a flapper which was not leaking leaks after
cleaning? Much appreciated.

The rubber was ready to crumble and brushing it made it crumble?