hmmm I am sure I did it with open end wrench, what size are you trying? I don't think you can do it with a flare wrench, they are too wide. use a open end with 4 flats not two flats and a rounded butt.
it looks like I'm picking up a twin to your bodhi, only a tad more miles. 360K... I may wanna pick your brain for tweaks on her.