Can't get nut off LCA pivot shaft w/ poly bushing (shaft spins)

Remove the LCA by sliding it off the pin. Clamp the pin at the shoulder with vise grips.

What Jim just told you, or put a vice grip plyer, or channel lock plyer, up between the crossmember and the LCA, and clamp down on the shaft.

That's what i do at the wrecking yards, when I'm pulling LCA's off a donor car, and the bushings are totally deteriorated, and just spin, what your going thru with poly's.