On Jun 7, 8:46*pm, "james" wrote:
Most toilet tanks have a flapper flush valve. But I have one with an unusual
cylinder valve, like this:

http://www.mansfieldplumbing.com/v3/support04-03.html

It has developed a leak, so I need to repair or replace it.

Does anyone know how to take it apart? The tank sits 3 inches below a shelf
that's firmly attached to the wall, so it's hard to see and investigate.

Would I need to separate the tank from the toilet to replace this with a
flapper-style drain valve? Or just to replace the seal (if I can even find
such part)?

It seems to me that regardless of whether you repair or replace, you
are going to need more than 3" of space to work.

You might not even be able to get the tank off the bowl with only 3"
of clearance.

"firmly attached to the wall" could mean many things, but it doesn't
mean the shelf can't be taken off. Do you know how it is attached?