Fuel leak

If you want to replace a steel line with another steel line, use bulk brake line of the right diameter. There is usually a formed end to prevent rubber hoses from sliding off. The first step of performing a double flare works well. If it plugs into a fitting, you're better off just cutting out the damaged section.

It's common also to replace steel with rubber hose and hose clamps. You should still form the ends of the steel line so the hoses can't push off even though there's very little pressure in the return line. If you use rubber hose to replace the fuel supply line, always use fuel injection hose because it's rated for the higher pressures. Standard fuel hose from carbureted cars won't stand up to the pressures from a fuel injection pump.