Any Plumbers in the Nut House?

[The Professor]

Okay. So here's the deal. Hot water in the bath tub had been temperamental for a few weeks. I'd go to turn it off and it'd slip past the off position and turn back on again. I'd do it a second time (more carefully) and all was good. Didn't really think much of it.

Yesterday, it did the same thing ... except this time, it wouldn't turn off on the second try. I gan get it to the point where it's a slow drizzle; but I can't get it to stop. If I press in on the stem, the water flow stops.

So I read up and it seems (from all I've seen) that there's something wrong probably with the seat, seat washer, or stem.

Regardless, the solution involves loosening the packing nut so I can pull the stem and replace one or more parts. Well, the jackasses who remodeled the bathroom and installed tile didn't cut a big enough hole to access the packing nut. Not is there an entry panel on the opposite wall. So ... I got a Dremel, picked up a ceramic cutting bit, and went to town to widen the hole.

I've got it widened to the point of being able to get the second to largest stem wrench (glorified thin-walled socket type wrench) in the hole, but it's not catching on any nut. I put my pinky finger in there and can't feel the angled edges of a nut, either.

Q1: Is it possible to have setup where there isn't a packing nut in the valve/stem assembly?

Q2: Is there anything else I could do short of calling a plumber?

I'm really at a loss here ... feeling totally defeated by this damn hot water control.

More info: House built in 1960s. This may or may not be original hardware. I don't think it was replaced by the last homeowner when they did their remodel (or they would have understood the importance of making the hole bigger). It's a two-handle control, Kohler brand, with the diverter valve and hose to the shower both on the spout.

Anyway, if any plumbers in the house can help a Brother out, I'd be much obliged....