What bore MC? (is the pedal effort normal/travel normal just not enough "grab" at the (4) corners?. when you stand on it do the rears lockup first? What I'd start with is put it up on stands & run it in gear & see how the rears brake then spin the fronts by hand as a helper hits the brakes. That'd at least be a start. Others will chime in/advise further. PS Make SURE you are braked to a standstill before shifting to park etc (the illusion fools you cuz the vehicle ain't moving)