Hmmm, Is this mushey thing only occuring in the rear brakes? What type of Brake fluid are you running? As far as seals popping due to sillicon brake fluid keep in mind that sillicon is just very fine sand; the seals are affected more by the chemical it's suspended in. Seals are all designed to work with certain compounds IE don't put esther based fluid in a system designed for mineral or petroleum based fluids...
I'm using dot4 Valvealine break fluid from advanced auto. Thanks for the info on not crossing over types of fluids.
