In alt.home.repair, on Fri, 04 Dec 2020 19:48:23 -0500,
wrote:

On Fri, 04 Dec 2020 16:12:50 -0500, micky
wrote:

My current problem is that it leaks downstairs only when the tub is
being filled. Not when the tub is draining. If it leaks when
showering, I haven't checked but probably. (I use another shower.)

It sounds more like the stem inside the spout is leaking but that and
the faucet stems should be visible if you remove the trim bezels or
the spout. I would start with the bezels. There isn't much between the
valve and the end of the spout to leak. Typically there is either a
pipe nipple extending out of the wall into the spout or the spout
itself threads into the valve body (the 2 common styles). The valve
stem packing is trivial to do if the knobs come off easily. They do
make pullers for that. I have had to cut them off tho.

Thanks. What slows me down is that any testing will probably involve
more dripping downstairs. I could put a bucket there, but I'm not sure
where it should go.

But I'll get to it.

I replaced the washers, and maybe the whole stems about 5 years ago and
stopped using the tub 2 or 3 years ago. But I didn't replace the stem
packing.