GM-GMC: how to bleed abs brake system, scantool, bleeders

Question
i have change master cyc. rear wheel cyc brake lines . i have bleed all four bleeders . what is prper way to bleed abs miter vale. pedal is very soft

Answer
I don't know what year/make/model you are working on, however, in order to bleed the abs, you need a scantool.  They have an automated bleed program which runs the pump and cycles the valve to move and air that is trapped inside.  As  its running you open bleed valves etc, but it varies slightly for every vehicle.  This is likely something you will need a dealer to do for you.
Hope this helps.