[Supras] Spring removal from shock problems?

[Walker, Brian (Rich. Dist)]

On the stock shock mounts, the upper 'cup' has a flat edge to match that
of the threaded portion of the shock shaft to keep the shaft from
turning while tightening/removing the top bolt (cup holds the spring in
place on the shock) I remember when putting the Tokicos on my car
thinking on of the flat areas looked worn and could be a problem later.
I now have another set that I'm working on and am unable to remove the
top bolt (shaft is turning along with bolt) Shocks are aftermarket so
it's possible the flat edge doesn't extend as far as stock or that the
flat on the upper mount is worn. I have not been able to find a way to
removed this. Anyone else have any suggestions?
I've tried placing rubber tubing over the shaft while holding with
pliers but it still turns.
Thanks for any help,
Brian