ManWithAVan

I replaced the front brake calipers and hoses on my van a few days ago. The new equipment on the right works fine, but the caliper piston on the left brake refuses to retract when I let off the pedal. I tried another caliper, assuming I had received a defective one, but the problem still occurred. It's odd because the old right side caliper got stuck outward, and replacing the aforementioned parts fixed the issue immediately. The left side caliper was dragging slightly and I replaced it so it would not fail like the right one.

I tried some basic diagnosis as follows: Cracked the line loose at the MC, at the hose and at the caliper. The only time the caliper will back off, even slightly, is when I crack the hose loose from the caliper. It appears that the brake hose or hardline is holding pressure and preventing the fluid from returning to the MC. This doesn't make much sense to me because the hose is brand new and the problem didn't happen until I changed my brake hose. Additionally, replacing the hose on the right didn't cause any problems.

Is there something I am missing? My last idea is to disconnect the hardlines from the MC, plug the MC and use an air compressor to blow out the front left lines. If that doesn't work then I may try my old brake hose on the new caliper, but I doubt that will work.