How to Unstick a Stuck D2 Angle Blade

The front pivot is free and so is the left arm. If I pull the pin and try to pull the right side arm out, it is tightly stuck. If I pull on the arm it has loads of leverage on the pin. Pulling it hard by hand almost bends the arm a bit. I can jack or pull on the arm, but I don't want it to bend. The connecting pin holding it to the blade is probably 18" long, so the rust has lots of surface area. I am considering using a sledge hammer on the top of the pin with the castellated nut, but I hate to mushroom it. It seems like it should be a trivial problem, but it is keeping me from using the angle feature on the blade. I may just have to get more aggressive on how to beat on it until it frees up.

Pictures might help determine a course of action, but you might be surprised how a little bit of heat will help. Most of the time with rusted components its not a one and done fix it takes time and small movements to break it free. Once you start beating on things you're almost guaranteed to have to replace them, which is ok if that part is available, but 5j parts are sometimes hard to find.

Have a propane tank about the size for a grill? Get a weed burner and heat the pin areas up good then try working it back and forth.

I was imagining a different area......the ones with slides down each side....not your style of blade....
Your saying the triangle at the blade won't swing out?
And the pin goes through more than one slot?
heat and beat
or cut out the exposed part of the pins and directly beat out the corroded in pin left in the blade mount

If you have access to a mag drill, you could drill the pin out

Is it the pin for the blade angle or for the blade tilt?

Raise the blade and or dig hole enough to get a LP turkey roaster burner just under the pin area - run on high sit back relax have a burger. Pull out burner and immediately pour buckets of cold water on pin. Do again making sure you use a hose or buckets of water.