[luvbowties]

You said, "why are the castle nuts not spinning on the thread? is it common to use loc-tite or something similar? If so, (I'm referring to the outer tie-rod here), how do I brace/hold the bold so I can get the castle nut off?"...

Sounds like the tapers do not fit or match--the rod is too small for the hole; else the taper should hold the rod enough to remove castle nut. No loc-tite ever commonly used.

TO REMOVE: Most times, use of an impact wrench will work: its quickly accelerating torque usually removes the nut even if rod is not snugly held by taper. If you don't need to save the tie rods, and looking like you're determined to return to original, a couple of techniques that may work: (1)use a pickle fork to "bind" the tapered rod enough to remove castle nut; if lucky, you may still be able to save that tie rod. (2)Use a pipe wrench to twist & torque tie rod/tapered rod into enough bind to allow removal. (3)Use a high-speed dremel tool with a small-diameter, abrasive cutoff disc to slice thru castle nut. You may need to chisel the final bit.

Hope this helps. sam