5000power steering hose to be replaced

[Dave1953]

Recently the high pressure power steering hose ruptured righ above where it attaches to the cylinder at the flair nut. 3/4" wrench is too big & 11/16 too small. 18mm is too small and 19mm is too big. We haveused flaoe nut wrenches, crows foot flair nut wrenches, nothing works. Mine is an early 1968 model with the cylinder under the rediatir. Son sways to cut the steel line just above the nut and use a 6 point sockey. Any ideas, I need help.