Trakrat

I took pb blaster and soaked it... next day soaked it again... a couple of days later soaked it again. Used about half the can. Finally took an allen wrench and hit it with a hammer to move it a couple of turns... still difficult and soaked it again in pb blaster.
Finally decided hell with it... I'm either going to break it off or remove it properly. hammering the allen wrench turned it slowly, but it finally came out.

sugarwood

Do you have Allen sockets?
Putting this onto a long handled ratchet is the only way to go.
I have not used an L-shaped Allen wrench in years.
https://www.amazon.com/Neiko-10074A-.../dp/B000GYLGU8
http://www.homedepot.com/p/Husky-3-8...BSSR/203559457

sugarwood

Putting the hex socket onto an impact gun would have ripped out the bolt in seconds.
Proper tools are the key to this hobby.