[Steeveedee]

Have you adjusted the rear calipers so that the pads are almost touching the rotors? If you try to bleed them without the resistance of the pad to rotors, you could just be cycling the pistons in the calipers. I'm not intimately familiar with rear discs, but I've seen where not being properly adjusted was an issue. The fronts don't use a parking brake for the take-up due to wear, like the rears do.