sliming the bottom of my left foot when im sitting in the drivers seat.
so as far as the couple of spare booster.master cylinders from poor past canniblized heaps,
Its kinda like an old carburetor i think soaking it i gas over nite -
the inner shaft seal, do i just pour on some 'jizzum" to wet it first so it dosent screw up from dry action when i swap it out?

Doesn't really matter as long as you can get the nuts and bolts loose. The master will need rebuilt or replaced and I'd change the booster, too. The master will leak into the booster and usually will eat the diaphragm - and you don't want to find out the hard way that the booster is shot. I'd swap them as a pair.

If you have a used set I'd check for a master with a good bore (no scratches, etc.) and rebuild it. Then look for a booster with no signs of fluid in it. If you can get some of those long Q-Tips like they use in a lab you can probably swab the booster and see if there's any fluid inside. As long as the booster is dry I'd expect it to be OK.

I'm not sure if Mercedes brake lines tend to seize up where they leave the master but if they do remember that heat is your friend. While I'd rather not torch brake connections it's sometimes the lesser of two evils.

Dan