Reaching it and keeping the wrenches on. I have the 24mm special flair wrench from Geno's Garage to hold the tube and a Gearwrench flex-flare-nut wrench on the line. I just can't get the 19mm flare nut wrench to stay on, and I don't think I can get the 19 mm flare socket on there. There must be a way to do it, but once that retaining nut moves, I have no choice but to pull it out.