I would check your brake lines to make sure that they are clear all the way from the caliper through the ABS unit and to the Master Cylinder. I have seen corrosion in brake lines do some strange things. How does it feel when you bleed the lines? Do the other 3 wheels work just fine? Raise your car so all the other wheels are off the ground, and then test all of them. See if any other wheel is sticking, also try the old parts. Did they stick as well?