Toilets, Sinks, Showers, Tubs and Disposals - Old cast iron tub drain

We have skirt cast iron tub, 1.5 inch? brass drain has large cylindrical plunger to stop/plug the drain. Water will not drain from tub. Cannot free this drain stop, took apart the lever at top, and pulled on metal flat rod which extends down to bottom of brass drain pipe, other end of metal strip or flat rod has plunger/plug. Can not free plug at bottom of pipe? 100 year old Hardware store that carries older plumbing suggested dish soap down top of pipe where lever was taken off to access top of brass drain pipe. Tried that, still stuck. I dont want to replace entire pipe and drain stop if I dont have to, parts are about $48.

Anyone have any ideas on getting this plunger free?

Shall I get out the monkey wrenches and turn these pipes into 20 pieces? Any thoughts on best way to put back together, dope/washers/pipe tape?

If I do get it un stuck,
is there a special heavy grease that is use on these parts to keep them lubed?

Thanks for any ideas,

Any luck yet?

Has this been easy to work up until yesterday, and suddenly became stuck? Any thoughts on your part as to why?

Brass drain stopper still stuck. Only person who uses tub regular is young teen age boy, not sure if small plastic bit of toy could have gone down pipes or what ever. I will have to get out the wrenches soon and tear into pipes.
Was trying to save better part of days work removing pipes, clearance is minimal.
Did notice at big store yesterday, stopper and rods can be purchased separate, under $10. Also noticed a choice of replacement stopper in plastic or brass.
Maybe I'll get lucky and wrestle that linkage and stopper out of pipe and just replace that instead of removing the whole drain pipe assembly.

I would think brass stopper is better replacement part than plastic, is that a rational conclusion?
Is there any kind of "bear grease", or "never seize" that is available for plumbing parts?

Thanks,

Plumbers grease I use all the time.

Is there ANY movement in that linkage? Do you still have the rod that goes down the overflow tube stiill attached to the cylinder? If so, can you clamp onto it with a vicegrip and rock it on the overflow hole (that you would protect the edge of it to not chip paint)

Stop cylinder is out! Sprayed WD-40 down the overflow and clamped
metal rod with visegrip, firm yank, and whole linkage is out! I think I'll put back the lever/cover on overflow, an get rubber stopper for inside tub as in old days.

Thank you for the input, so glad didnt have to tear into the pipes,, too much labor for the small bit of trouble,, this forum is great!

(maybe when I have nothing better to do in a few months, I'll put new linkage back in, thanks again!)

Whew! Glad you got er. While out, you might want to polish up that cylinder.