Bleeding brakes...

I've had a bit of trouble with ABS systems too.It's always after the unit that trouble starts. I have had better luck with the 2-person bleeding method.
I remember this one GM car Where I finally figured out that the ABS unit was seized inside. I replaced it with a used one and then it all worked out. But, man it is hard to condemn an ABS unit;they are not cheap.IIRC, some of those require special procedures.
Sorry, I can't be of more help. I try to stick to things I know, and ABS is not really one of them.
Ask me about running 11.2 Scr on 87E10.......