Stainless steel will rust, there's no way around it. I just rusts a lot slower than carbon steel
Steve O - It's my opinion that stainless steel brake lines are okay to use, I've heard nothing about the brass fittings. That would depend on any finish coating on the fittings. There is nothing wrong with regular steel lines, as long as the fluid is maintained and you don't let dirt or mud accumulate on the lines. Then they rust. On my 52 all of the original steel lines are original save for the one on the rear axle, it was coated with mud and thin.
The biggest problem with the SS brake lines comes with the heat treatment and bending. One of the companies sells them in an annealed (soft) condition, which will allow you to do some bending to fit your truck.
