Chevrolet Repair: Anti-Lock Brakes, rear shoes, rear brakes

Question
I have a 1995 4DR 2WD Tahoe with the 5.7 engine and 111,000 miles on it. I have replaced the master cylinder, both rear cylinders, both front calibers and all the brake pads. I have bled the brakes. The pedal is still mushy. The anti-lock brake light is not on and I do not have any error codes. Do you have any ideas, short of just replacing the anti-lock brake assy.
Do you have any ideas?

Answer
Hey Ron,

  Make sure you have the adjustment of the rear brakes dead on.  If the shoes are loose they will cause the cylinders to retract and cause a low pedal. You can verify this by pumping the pedal and if you can pump it up and hold it firm and it doesn't drop until you release it then its the adjustment of the rear shoes.
  Even if the modulator is defective it won't cause a low pedal unless it is leaking.  There might still be air in the system and they can be difficult to bleed.  We have power bleeding system and I still have to do the autobleed with a scan tool.
 If you have a vacuum pump you can pull one bleeder at a time and draw a couple of ounces of fluid out of each wheel.  That should help get the  air out.  You can eliminate each hydraulic component by carefully pinching it off with needle nose vise grips.  Some flex lines can be damaged this way but I don't think a 1995 Tahoe will be affected. Pinch

Wayne