I had a helluva time getting the AN fitting out of my Christen 802 Air / Oil separator. The fitting was less than finger tight, but it galled up badly. Not even heat and WD-40 would loosen it up and I ended up bending the main barrel and tearing threads out before it would budge. I'll either have to weld in a new weld-boss and tube or buy a new separator. Bugger.