Brake Master Cylinder: Description and Operation

This master cylinder contains a double hydraulic cylinder with one fluid reservoir on Aerostar models or two fluid reservoirs on other models as well as primary and secondary hydraulic pistons. The rear wheel brakes are connected to the secondary outlet port and are actuated by the secondary piston assembly. The front wheel brakes are connected to the primary outlet port(s), nearest the dash panel, and are actuated by the primary piston assembly.