fork caps

try heating then smack the center of cap with a hammer spray with zep 45 then hit em with imact!did i miss anything?

Why not use a socket but make sure its a 6 point and not 12 otherwise it may slip (as you said you tried that) but put a 4 foot pipe on it. I have loosened nuts this way that an impact gun wouldn't.

is it loose yet...is it loose yet

It ain't loose yet.
I talked to the guy that put the fork caps on and he told me he used an air impact driver. He must have thought he was tightening lug nuts. He wants to drill them out for me at no charge. I would let him do that only as a last resort.
I have been using a 6 point socket with a breaker bar and then and air impact & it just rounded the nuts.

Next I'm going to look for an easy out socket (sears maybe) and try that with a 4' breaker bar. And, maybe some dry ice if I can find any.