How to Flare a Brake Line

The brake lines of your vehicle use compression fittings to maintain pressure within your vehicle's brake system. It is vital to the safety of your vehicle that the brake system functions properly. A vital part of servicing or installing a brake line is properly making the connection between the brake line and the components of your vehicle's brake system. To make a brake line connection using a compression fitting, you need to flare the end of the brake line tubing before seating it in the compression fitting.

Difficulty: ModerateInstructionsThings You'll Need:

Brake line tubing
Tubing cutter
Reamer
Compression fitting
Flaring tool with vise

Step 1
Cut the brake line tubing to length with the tubing cutter.
Step 2
Insert the tapered end of the reamer into the end of the brake line tubing that you cut in the previous step, then twist the reamer around the inside of the brake line tubing to remove the bur from the inside of the brake line tubing.
Step 3
Slide the nut of the compression fitting over the end of the brake line tubing, with the female threads of the nut facing the end of the brake line.
Step 4
Loosen the wing nuts on the side of the flaring vise to allow the jaws on the flaring vise to open, then slide the end of the brake line tubing into the opening of the flaring vise that matches the outside diameter of the brake line tubing.
Step 5
Align the end of the brake line tubing with the top edge of the flaring tool vise and tighten the flaring tool wing nuts to secure the brake line tubing in the flaring vise.
Step 6
Place the flaring tool over the flaring vise and align the tip of the flaring tool with the opening of the brake line tubing. Read the operating instructions for the flaring tool to determine how to secure the flaring tool to the flaring vise.
Step 7
Turn the handle of the flaring tool clockwise to force the tapered tip of the flaring tool into the end of the brake line tubing. Continue turning the handle of the flaring tool until the brake line tubing is forced tight to the edges of the flaring vise.
Step 8
Reverse the direction you are turning the handle of the flaring tool to remove the tapered end of the flaring tool from the end of the flared tubing.
Step 9
Loosen the wing nuts of the flaring vise and slide the pipe from the jaws of the flaring vise.
Step 10
Inspect the flared end of the brake line tubing to ensure that the end of the tubing is not cracked from the strain of flaring. If you notice cracks around the flare, cut the flare from the end of the tubing and repeat the steps to perform another flare on the end of the brake line tubing.