Forming Brake Lines at MC/Proportioning Valve

[Alan_C]

I plan to incorporate the stress relieving pigtails, corkscrews, or whatever they are called in the brake lines as they exit my proportioning valve. My brake line is 3/16 inch Cunifer (Nickel Copper). In my first mockup, I used two 1 inch diameter 360 degree loops, is that enough or should I increase it to three loops? My MC/PV setup is in the engine compartment and I want to make sure the brake lines are tolerant of some vibration without metal fatigue.

[cob427sc]

I would guess the 2 turns are plenty. Obviously there is some vibration that occurs in the lines, but I'm not convinced that adding the loops doesn't actually increase the vibration. Many factory built cars have no loops leaving any of the brake components and fatigue/cracking of the lines does not seem a problem.

[Ian G]

If you do make vibration coils try to keep them as horizontal as possible. That will help prevent trapping air when bleeding the brakes.

[Avalanche325]

Those coils are really for making up for manufacturing tolerances on production cars. That makes it easy for the assembly line. I got that from a GM engineer. A lot of new cars don't have them.

Any hydraulic shock in the system would be taken up by the flexible hoses, and everyone does whatever they can to minimize that. Cunifer lines are soft in the first place.