rebuilt both master cylinders with OEM parts as well as all threecallipers. The pistons looked ok. maybe some pitting but I felt nothing bad. cylinders looked great after cleaning. Will order new pistons.What did you do to the master cylinders? Replace o-ring/seals and crush washers (OEM or something else)? What condition was the piston in when you removed it for cleaning? Pitting or scaring? Did the diameter measure within specs? What about the cylinder? Pitted, scared?