In the United States, vehicles use a double flare brake line system. First place a nut on the end of the brake line with the threads facing the part to be worked on. Cut the brake lines evenly if needed. Clamp the line and use a brake line anvil to make double flares. Adjust the brake line to the mark on the anvil. Tighten the anvil and place the raised end in the brake line’s center. Clamp the flaring tool over the anvil and tighten until it is flush with the anvil. Fit the flaring tool over the tubing center and tighten again, forming the double flare. This must be perfectly centered.