DSTJohn,
I'd bet you have OEM brake line crud clogging the caliper. That's what I had last winter, caused my front brake to lock down, acted as a check valve inside the caliper passages. I disassembled and thoroughly cleaned the calipers passages (both sides). That' the ONLY way you can clear the passages. Stupid simple, four bolts and one O-ring.
I replaced ALL the hydraulic lines with Spiegler. Much better than Galfer, just because of the tools they provide.
All the pics are here:
https://photos.app.goo.gl/vdJIe8VNu17u4Z9N2
This was the problem:
