To remove the brake proportioning valve, start by placing rags under the brake line fittings and preparing caps or plastic bags to cover the ends of the lines once they're disconnected. If the vehicle has a RWAL system, remove the RWAL module. Then, use a flare-nut wrench to loosen the tube nuts at the ends of the brake lines where they enter the brake proportioning valve, making sure to prevent rounding off of the flats on these nuts. Plug the ends of the brake lines to prevent contamination. Unplug the electrical connectors for the low-pressure warning switch and, if applicable, for the anti-lock pressure valve. Remove the brake proportioning valve mounting nuts (which are also the mounting nuts for the master cylinder) and remove the brake proportioning valve and bracket as a single assembly. Finally, separate the brake proportioning valve from its bracket. To install the brake proportioning valve, simply reverse the removal steps, ensuring that the brake proportioning valve retaining nuts and brake line fittings are tightened to the proper torque specifications. After installation, bleed the brake hydraulic system.