Sounds silly, but are you sure your are loosening the bleeder valve enough?
When I did my brakes about a month ago it was the first time I had ever done this. I discovered at first that I was not loosening that nut enough. Made life much easier once I did. And this is on my 640 adv.
I suggest also reading this:
And I also suggest getting a mity vac. Best $40 I have spent in a long time. Made the process of bleeding my brakes a no-brainer.