If the fronts are sticking then you probably have an incorrect component in the system such as the wrong master cylinder (drum Master instead of Disc master), perhaps the incorrect proportioning block. The reason Mine stuck (and very light braking would lock all 4 corners) was that I was using a Drum brake booster versus a disc brake booster. My troubles went away when I found the culprit. Spindles themselves wouldn't cause sticking, the whole wheel rotates on the spindle. Maybe you have a problem with crud inside the caliper (or wheel cylinder if you have drum brakes) where the piston is.

I mention wheel cylinders because you were not clear on whether or not you had upgraded to disc brakes in your post.

What system do you see on there now?