560SEL/M117 EGR Seal Removal

[Golden80s]

Hello all,


Any thoughts or tricks on how to remove a recalcitrant brass/bronze compression seal from the rear EGR pipe on a M117/560SEL?


Took off my EGR valve without any real difficulty at all (knock wood) and most everything came apart nicely with two out of the three compression seals popping right off. BUT - the third just spins freely and nothing I've tried so far can induce it to move forward off of the pipe.


What has been tried so far is a combination of AC Delco penetrating oil, vise-grips, and knocking the 24mm nut forward with a 20mm wrench and rubber mallet.


Nada. Won't budge. Just spins around and around mocking me.


Any ideas short of extreme heat or grinding?


Cheers!