I have used copper tubing (as a replacement) on non power assisted brakes many years back. It was a common practice then and the material lasted forever. I never had any issues with it while I used it but it was eventually outlawed as not being strong enough to take the increased brake line pressures.
Originally Posted by madbrad
Now they are making steel brake lines more like copper and copper brake lines more like steel. Stainless steel sounds like the solution but to get the bending and flaring capabilities might require a low grade of stainless that will eventually rust.
2007 GC SXT - Magnesium - S&G - 3.8L - 145,500 kms
2002 GC Sport - Stone White - 3.3L - 328,350 kms
2003 Jeep TJ Sport - 4.0L - 258,980 kms