Here is the way the dealership removed and would still remove the front brake hoses on our trucks :
1 spray penetrating oil on nuts inside and outside frame
2 remove outer frame c -clip
3 push hose into frame slightly now you can remove the large flat nut ,just let it slide over the steel line for now
4 push hard line thru frame enough so that you can get a line wrench on and a second wrench on the rubber hose side
note - since the hard line nut will likely be worn down from the elements its netter to use vise grips and lightly clamp down on the nut use this to hold the nut while unscrewing the rubber hose away with a wrench -this way you never have to worry about twisting off a steel line .
5 replace in reverse -
ive noticed alot of info and videos that are painfull just to watch - it isnt suppose to be that way .