This discussion has raised a question in my mind. Since the changing fluid maintenance had been done on my car, I concluded that changing the brake pads in other than the MB manual described manner must have been what caused my problem. I didn't have the special tool, just did my best to press the pistons back squarely without it. May not have succeeded.
Has anyone else had a similar experience and what other thoughts does anyone have about this?
Thanks for any observations and comments.