With ABS brakes, there IS a pump. The ABS pump. It is not the master cylinder. The ABS pump along with the electronics and wheel sensors apply braking to the wheels that need it.

The ABS pump needs bleeding too. You first bleed from master cylinder to ABS pump. You crack the pump connections one at a time with pressure bleeder connected and wait until there are no bubbles. Then move on to the next one. Then from pump to wheels in usual way. Again you need to use a pressure bleeder. 20psi applied at brake fluid reservoir will do it. You need pressure to force the fluid through the pump. You can buy pressure bleeders or make one yourself.

If you try and bleed by pumping the pedal, you need to close the bleeder screw every time your assistant lets off of the pedal. Otherwise air gets sucked through the bleeder threads. You also need to keep the reservoir filled - even with the pressure bleeder.

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5