Frank,
I'm innocent. I always use vise-grips to bust the fittings loose, then you can use a flare nut wrench. My experience has been a flare nut wrench will not break a tight nut loose..only round it over. I was hung-drawn-and quartered for my opinion on this subject, but I'm sticking to my guns.
Remember as you work on the newer rigs, all engineering decisions are based on $$$. Somehow, it was more cost effective for GM to use that size flare nut.
Stuart
