The drum brakes on vehicles with front disc/rear drum brake units have rigid springs that retract and maintain the rear brake shoes in following brake application. The location magnetic discipline sensor detects the motion (the end place) in the metering piston and, consequently, the objection on the lubricant. Its output http://valvesandfittings95284.tribunablog.com/the-best-side-of-metering-valve-8833008