The vehicle is a Ford e-350 7.3L DSL. We have survived the brakes completely failing four times. My mechanic, who I trust, insists it is a Ford problem and that each time the Motorcraft Vacuum Pump fails, bearings freeze causing pump to lock up, this leaves us with no brakes. After four scary events, and my not finding any deaths from other owners of the same vehicle, I am beginning to wonder. Any insights?