I'm replacing the valve stems for my 1960's bathtub handles. There's a hot and cold handle, and they both are leaking profusely from the stem (not drips, but streams of water).
This picture generally agrees with what I've seen so far - previously I tried to replace the entire valve stem, but I don't think it's made anymore. The closest I've found is a Danco 10B-9H/C (https://www.danco.com/product/10b-9hc-hotcold-stem-for-gerber-faucets/), but the stem has too many threads to fit my fixture.
I replaced the seat washer, and re-greased it and the bonnet washer (could not find a replacement for the bonnet washer). This fixed the original problem, which was regular dripping from the faucet itself. Now the handles are spewing water when they are turned on. From inspection, it looks to be leaking out of the inside of the packing nut. Based on the picture above, I think it is because I destroyed what little remained of the original packing washer (I soaked the valves in alcohol and cleaned them internally and externally with steel wool). This means that the water is sneaking by the stem threads and leaking out of the front of the packing nut (facing into the bathtub).
Knowing this, I think I have a few solutions. One, I could use graphite packing string on the stem threads. Two, I could use teflon tape on the stem threads. Or three, I could use plumber's grease on the stem threads.
Which of these choices is appropriate? Stem threads regularly move (anytime you turn the handle), so I'm not sure any of the above methods could handle that regular motion. I can't find any information telling me if they can. However, I can't locate a new packing washer or stem.
How should I repair this leak?