2. Jeep used assorted sizes of ferrules to plug into the factory proportioning valve. The Wilwood unit has all of the ports set up to receive the same size: 3⁄8-inch with 24 threads per inch. Fortunately, despite the various ferrule sizes from the factory, the lines are the same size and Wilwood provides new ferrules. So, using Summit Racing’s Double Flare Tool (PN SUM-900310), we were able to cut the lines (always use a tubing cutter), remove the goofy sized ferrules, and put on the new ones supplied by Wilwood.