Re: Double Flared Tubing

Posted by BH On 2006/12/19 20:15:17

I used to think stainless was the way to go, but I have to agree with Keith about avoiding stainless steel lines. Getting stainless to seal against cast iron seems to pose a problem.

Bending your own lines is not that hard, with the right tools, but be sure to get a good quality flare tool and make a couple of test flares to confirm that it works properly. I have one that the dies didn't quite line up perfectly, and I freqeuntly got leaky connection as a result.

Getting back to materials, if you use DOT 5 (silcone-based) fluid, you minimize the problem of moisture being drawn into the system and causing the steel lines to rust form the inside out.

However, do NOT use DOT 5 in any ABS brake system.

Also, NEVER use copper for brake lines.

Always use double-walled steel lines for hydraulic brake applications. Tubing with polyvinyl fluoride coating is now available, but I would avoid that, too, as the coating tends to crack at bends, holding moisture, which leads to rust. I am fine with the traditional zinc-plated stuff, but have used some spiral shield (as found on modern cars) to prevent road rash in highly vulnerable areas.

You should be able to get 25-foot coils of double-walled steel tubing from any reputable parts store. The stuff sold in coils seem easier to bend and flare than the pre-flared straight pieces that are available in assorted lengths. If you use the latter, be sure to check with the store to make sure you get the rigth type (45-degree double upset) for your car.

Some people use copper for non-hydraulic lines and some even paint it with alumminum-colored paint. I just use steel for everything.