How to Use a Flaring Tool

• Flaring tools are described as either single or double flare. Both work the same way, but the double makes a stronger, safer flare. The single flare is a one-step operation and forms a flare from a single layer of the tube, while the double first forms a bulged out area in the end of the tube, which is folded over itself to make a double-layered flare during the second step.
  The largest part of a flaring tool is the tube clamp. This clamps has several holes, which are marked for the various tube sizes. Loosen the wing nuts to allow the tube clamp to open and insert the tube into the proper-sized hole. Set the small flaring adapter--this is the small disk with the stud protruding from one side of it--upside down beside the end of the tube and adjust the tube to stick out of the clamp the same distance as the thickness of the adapter disk. Tighten the wing nuts securely. If they are loose, the tube will slide in the clamp and ruin the flare.
  Attach the flaring screw to the clamp. It attaches by sliding down over the clamp and twisting sideways to hold it in place. The cone on the end of the flaring screw should line up with the end of the tube. Place the protruding end of the adapter disk inside the tube, using brake fluid as a lubricant. Tighten the screw against the back of the disk until the disk is pressed against the sides of the clamp and then back the screw off and remove the adapter disk. Add another drop of brake fluid to the end of the tube and tighten the cone of the flaring screw into the end of the tube until it stops.
  Loosen and remove the clamping screw and set it aside. Loosen the wing nuts and remove the tube from the clamp. Examine the flare. It should be uniform and without any cracks.