3/16" is the size most brake circuits use, and copper-nickel is the material to do it in once. Every line here is 3/16-inch copper-nickel (CuNi 90/10) -- it never rusts, bends by hand without a bender, and forms both SAE double and DIN bubble flares.
Why 3/16" copper-nickel
If you're replacing a factory line, 3/16" almost certainly matches what's on the car -- check the tube nut to be sure. Copper-nickel is the easiest material to route and flare, and it's corrosion-proof for life, which is why it's the go-to for Rust Belt daily drivers and restorations alike. It meets SAE J1047 / ISO 4038 and is street-legal in all 50 states.
Shop all copper-nickel brake line, step up to 1/4" copper-nickel for rear runs, or add the fittings and a flaring tool to finish the job. Browse all brake lines.
