I ever knew anything about them until I bought a Volvo, when I put it in the air I was very surprised to see it had copper brake lines from the factory, especially since Volvo is well-known to go the extra mile for safety.I have not yet used the nickle/copper brake lines personally, but I understand that several OEMs in Europe, such as Mercedes and BMW are using them on their production vehicles. (Probably is being used in USA OEM applications too, but I don't have valid information on this subject at this time)
I have ni/cop on my car and its been good. It couldnt be easier to work with, however the only complaint I had in the beginning was making flares. You have to learn to not really tighten ot down like you would steel lines. I made the mistake of tightening it too much and it actually smashed down the flare to where it leaked out of the fitting. I made a new flare about 3 times before I figured out wtf was going on. Other than that its worked great for me and been on my car about 2 years now.Has anyone ever had a failure or puncture of the nickle copper line compared to steel? I know to build for worse case scenario.and steel is stronger. Just wondering if anyone has used it with good or bad results.It is so much easier to use.