On Sat, 10 Sep 2011 11:55:29 -0400, "RogerT"
wrote:

Nate Nagel wrote:

I'm having a hard time visualizing, probably because I've been up late
every night this week either playing with power tools or huffing flux
fumes. On a typical older stop and waste valve, if I shut the valve
off, can I remove the packing nut and shove some more packing in there
without having the water shut off *prior* to that valve?

I think the answer is "yes", you can shut off the valve and loosen and
remove the packing nut to add valve stem packing. I just had to do that a
few weeks ago with an old toilet supply valve. I just shut it off without
turning off the water supply anywhere else, then loosened the valve stem
nut. In my case, even repacking the valve stem didn't work because it was
an old and corroded valve with a bent valve stem. So I had to replace the
valve after trying the repacking trick first.


You can usually stop leaking past the stem by adding some packing.
The caveats are
1. Don't strip the packing nut.
2. The valve will become hard to crank because of packing pressure on
the stem.
That might clear up without leaking again and it might not.
I've had mixed results adding packing.
Better when I used square packing material closely matched to
stem-to-case diameter.

Original valve packing is designed to a diameter that fits almost
exactly between stem and valve body. It doesn't take much compression
to seal.
The right way to repack a valve is to remove all old packing and put
new right-sized packing back in.
I'm in the replace old valves camp, unless that's not practical.

--Vic