one of the metal lines (can't see which one) running across the top of my frame rail has rusted through right behind the body mount area where the frame angles back up in the wheel well. I am having a hard time figuring out how exactly i'm going to get into this little tight area to replace it. Any ideas?

 

Work with what you can access and replace all the way to the other end where ever you can get access. All you need to do is get enough good line to put another good flare on and then use a union to connect to the new line. Just leave the old line up there.