GM nv4500 pivot ball replacement

[BigMotherTrucker]

Hello all, I have a 94 k1500 with an external slave cylinder nv4500 as the transmission. I'm in the process of repairing truck after a throwout bearing failure. It looks like the clutch release fork is trashed so I'd like to replace it. The pivot ball that the fork is mounted doesn't look completely destroyed like the fork is, but I would still like to replace it. The only thing is, I cant seem to find any solid information on how to remove it. On the external side of the bell housing the pivot ball looks to be removable by unscrewing it with a large allen wrench, however I put quite a bit of muscle to it and it wouldn't turn, luckily I didn't strip it.

Is this simple a case of needing a bigger wrench? Or is there something else i need to do before the pivot ball is able to be removed?

Thank you for any help you may be able to provide.

 

[BigMotherTrucker]

I was able to get it out by torching it, though I was hesitant to because the bell housing is aluminum. If anyone in the future has the same problem and stumbles across this post, it appears there was red loctite or rust - some sort of white residue- across the top rim of the pivot ball, not on the threads, so there shouldn't be any need to torch the internal end of the pivot ball where the fork attaches to it. Once that broke free it screws out and in very nicely.
it's not pinned in place or reverse thread or any thing strange like that, I used a 3/8 inch Allen wrench to remove.

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