Dual Piston Master Cylinder (AEROSTAR)
Aerostar models use a Recessed Cartridge Master Cylinder (RCMC). This master cylinder contains primary hydraulic springs and pistons, secondary hydraulic springs and pistons, plastic fluid reservoir with fluid level indicator, integral bypass proportioning valve and differential pressure activation system.
Rear brakes are connected to the secondary outlet port and are actuated by secondary piston assembly. Front brakes are connected to the primary outlet port (nearest dash panel) and are actuated by the primary piston. This master cylinder can not be overhauled. If found defective it must be replaced.