In my old 4000Q, I too experienced a rotating
sensation (reality really) when hitting the brakes.
It wasn't the brakes at all. It was my rear
control arm bushings, or lack of same.
The bushings were toast, the wheel was "cocking"
(severe toe change), and the car was making
an abrupt and disconcerting change of direction.
Often, at speed, I felt I was going to hit a wall :-()
Check the bushings, front and rear. They go, and go
quickly. You will greatly prefer the car once they are