I'd get an Allen-head socket and put it on a breaker bar. Then you can slip a cheater pipe over the breaker bar for more leverage.

^ so, brute force, then.

that scares the hell outta me. but maybe that's the way....

Probably steel-on-steel rust and yes: brute leverage is you friend but take precautions to keep your knuckles and the frame from damage.
I'd say you could benefit from something better than "light oil" to help free the corrosion: I favor Kroil, but the "ghetto" formula of 50-50 mix of common auto transmission fluid and acetone often works wonderfully well. Plus you can buy the ingredients in nearly every place in the developed world...cheap, too.
Don't forget HEAT: warm that area with a propane torch...gently...you want it to get hot but not scorched or on fire.

applies brute force ... "ping!"

i got it! when i heard that sound, i didn't know what happened. scared the bejebus outta me. but it finally succumbed to 'brute force.'

good film noir, by the way.



thanks again, fellas.

Leverage is always the correct answer, not 'brute force', which sounds like pounding with a hammer (or fist).