Trying to help my mom with her bathtub plug control lever... it’s jammed. I removed the faceplate and the cotter pin which linked the control to the two copper pieces which appear to be linked to the threaded rod. Threaded rod assembly is not moving freely up and down and I can’t pull it up and out to remove it. When I jiggle it around I think I hear metal on metal.

Any tips on what to do to get it working again?

squirt some penetrating oil down the overflow pipe.
grab the threaded rod and pull harder..
it should come out.
here is what you are dealing with..

here is probably hair and or debris where the plunger seals the drain to fill the tub water.

Appreciate it. Will try to clear it out next time I’m at her house.

That picture is very helpful because it explains the metal-on-metal sounds I heard... so it’s only the first piece I was moving at all.

More likely, it has not been used as a tub for a long time and the sliding plunger is corroded in place.

Hj - yes it hasn’t been used for maybe 20 years as a tub. Can anything be done in that case? Short of replacing the whole tub drain assembly (this will involve breaking drywall as there’s no access panel)

I have almost always been able to free them up, but it often takes several different processes. Fortunately, if you can get it to move even a 1/16 of an inch it should pop right out. Use a lot of WD-40 and Liquid Wrench down the overflow pipe around the edges,and wait a day or two.