Somebody knows the answer

[FishStretcher]

I might suggest spraying brake cleaner with the little pipe to clear corrosion products out, then hit it with diet coke or naval jelly and a sonicaire toothbrush to rattle the cotter pin when surrounded by phosphoric acid.

Just a guess, but it is easy to try.

Actually just reread the text- it seems you have the cotter pins out?

If that is the case, then I vote for kroil. Hit it with non chlorinated brake cleaner to get out the PB blaster and spray kroil and let it work overnight.