Start with removing the left turn signal housing and the extension panel there which is below the opening in the left turn signal housing, when servicing and repairing the brake proportioning/combination valve. Disconnect the horn wire, lift off the access panel and get rid of the screws holding the washer reservoir in place. Lift the reservoir to unplug the pump motor connector and remove the pump hose and then free the reservoir from the engine compartment. After that, take off the pressure differential switch wire from the combination valve and remove the brake lines from the switch side of the valve. From above, remove the other two brake lines from the valve using the access cover opening, then pull the valve mounting bolt and remove the valve through the same hole. For the installation, attach the valve onto the bracket and fasten the mounting bolt to 24 Nm (18 ft. lbs.). Fit the brake lines and then tighten them up with a wrench to 13 Nm (115 in. lbs.). Whenever possible, mount the washer reservoir with the pump motor connector and pump hose in the engine compartment. Next, remove the horn connector, install the access cover, reinstall the extension panel and attach the left turn signal housing. Don't forget to finish by filling and bleeding the base brake system.