update: Today I changed out the distribution block and bleed the system. Tested car right side still locks up. I switched lines same ting. I ran new lines, Same thing, right side still locks up? The only thing I can see is the right side has a GM stamped caliper single piston and the left side has no markings , single piston. Maybe the previous owner bought a mismatched set? Im going to but 2 new front calipers, should they be single piston or double? It is the only thing I have not changed. Any ideas or suggestions? Tkx JIm F