I was hoping ford could replace just that nut as it is kinda stripped from the factory, like a malformed bolt, but of course they won't believe that.
Well no warranty so they will charge you.
If you put your stock brake lines back on they may do it for you since the remaining parts are OEM.
Your stock lines will work fine as they are what Ford also used on the Cobras. You'll just need new copper washers from the parts store