I have used the copper alloy brake line on two frame off projects, 1950 Chevy COE and 1937 Chevy pick up. As I understand it, this is called Cunifer (using the notations for copper, Cu and nickel, Ni in the name). This is used on some high end European cars. I had never done brake line work before, as I am not a mechanic but a retired pathologist. Not one of my flares has ever failed, leaked or split. As noted above, it is very easy to bend but it will kink if you are not careful. I have purchased the tubing, in 25 foot lengths from Fedhillusa.com. as well as their flaring tool. On the latest project I bought NAPA's version of the product and noticed the tube walls seemed thinner. I called Fedhill and they said they get their product from Great Britain, and they traded me my 25 ft roll for one of theirs. I compared the weight of each roll and theirs was about 18% heavier. Whether that makes a difference in performance I don't know. From now on, though, I will be buying their product for future projects or repairs.
Regarding using DOT 5, I have never used it but I have read you must be sure that all of the rubber cups in the cylinders must be compatible with silicone. I am not sure how you do that. Recently, I helped a neighbor with brake issues on a 70s RV he was restoring. The RV had the brake system converted to DOT 5 and the vehicle had been stored in Phoenix, not exactly a humid or wet environment. All of the cylinders were rusted and you could see where the water/silicone interface was. With conventional brake fluid, DOT 3/4, water mixes with the fluid. That is bad in that steel lines will rust from the inside out but it is also good that the fluid continues to function, and if you bleed the system occasionally, the water is removed. With silicone there is no mixing and it will layer out as I witnessed. I know there are people who have used DOT 5 successfully but I intend to stay with DOT 3 and just bleed the brakes occasionally as they were designed.
Kent
