On Fri, 20 Jul 2007 02:41:54 -0000, Joe wrote:

I noticed that water was leaking underneath my flapper gasket a couple
of days ago.

I don't think you mean "flapper gasket", just "flapper".

I reached down to feel it and the rubber started to
disintegrate so it looks like it may have been compromised. I went to
go turn off the water underneath the toilet and suprise - that doesn't
shut the water off totally.

You could put vice-grips on most handles and that will enable you to
tighten it more. That's what I have to do on one toilet. I put the
vice-grips on with the handle pointing awaay from the wall, since they
don't fit parallel to the wall, but it's still plenty of help.

So I'm going to have to turn off the main
to take care of this - that gives me another problem - the last time I
shut off my main a constant trickle still came out of the pipe.

You can solve most of that by turning on many or all of the faucets in
the house.

Everywhere I look online seems to only give instructions on replacing
the flapper - not the valve it connects to.

That's called the ball cock.

It seems like I'll have to
take the tank off the toilet to take the part off

I've never seen one where you have to take the tank off. Look at it
again. You undo a nut around the supply tube and separate the tube
from the toilet/ball cock**. Then you loosen and remove the big nut
right above where the supply tube/pipe was and remove the ball cock
from above.

**If there is still water coming out of the supply pipe/tube at this
point, you'll probably know before you remove it. But you can put a
dishpan under that side of the tank, and you can probably buy three
feet of rubber or maybe vinyl hose that you can slip over the supply
tube and put the other end in the toilet. Don't forget that the tube
is flared at the end so it's about a quarter inch greater in diameter
than the rest of the tube. Rubber stretches more than vinyl, but
maybe buy 5 feet instead of 3 and run the tubing you buy two feet up
the supply pipe/tubing and just tape it on there where it will
probably still be dry. Then put the other end in the toilet.

so that means I have
to find some way to drain the trickle coming from the pipe. It's a
little too much for just a bucket - especially since I need to take
the pieces to the store to match them up.

AFAIK almost everyone replaces the ball cock with a Fluidmaster, that
you can buy in advance. The advantage of this is that it has a
bayonet mount, as in camera lenses, and the next time it fails, it can
be removed from above and replaced in about 10 seconds. (That is, if
they haven't changed the mounting, and so far they've changed it twice
for me in 24 years, so I haven't had the benefit of quick change. But
I know they've had reasons, and maybe they are done now. I think I'm
only on my 5th or 6th one for 3 toilets in 24 years, with the second
set this yearso that's only one every 12 years. That also means they
only changed the design every 12 years.

The disadvantage seems to be that they fail sooner, but I might not be
in a postition to judge, since I've lived here for 24 years, and I
only lived in two other places that had ball cocks, one from age zero
to 10, and I was only paying attention from age 5 on, and one from
ages 10 to 17. They were still brass then, but it's only 7 years
instead of 24.

Is it possible to connect
some kind of hose to the disconnected pipe to drain the water into the
tub or toilet while I fix the valve? My brother-in-law seem to think
the valve leading the the tank might fit a garden hose.

The valve? Aren't you removing the valve? Do you mean the tube/pipe?
The tube won't fit a garden hose. I don't see how a hose clamp will
help. Even the small diameter garden hose I don't think you won't be
able to clamp down enough, in fact barely at all.