My solution was: a lot of heat Used my propane torch and to protect brake lines, I covered them with my welders gloves, because I couldn’t find any plumbers mats. Each bolt took around 5-10 minutes of constant heating and then serious impact gun action, but I got there :)
Cool! Glad you got it!
When you reassemble, wire brush clean and use an anti-seize compound. A ten buck jar will last years. I use Permatex nickel (silver, white 6 oz jar with brush in cap) for nearly everything.
Mostly it seals out water but the finely ground nickel metal dust does the work.
Also put the nut on the bolt, in your hand, and look at it closely: usually the stuck part is very small, the outside threads. But the nut against the part has a lot of static friction.
Spend time examining parts like this really closely, you’ll get a lot of insight into how this happens – and how to get out of it!
I am currently dipping the rusty parts in acid, will post another update of the process later in the community