I don't know man. I sure would suspect that master cylinder. If it is producing pressure before you press the brake, it may affect the right front first. Just a theory. If you bleed the pressure out, cap it, pump brakes, and it sticks until you bleed the pressure out again - then it sure looks like pressure is stayin' there and what else could do that ? Could be proportioning valve or ABS valve or solenoid I guess, not sure how to test the prop valve, but I've heard you can get the ABS unit out without too much trouble either disconnecting brake lines or bending them.

 

I took it fro a test drive today. The caliper started to lock about a mile into it. I pulled over and released the pressure from the abs module where the caliper line connects. It unlocked. Kept driving, testing the brakes. Again, same lock issue. I then opened the connection thats on the back of the abs module closest to where the right caliper line enters the abs module. Released pressure. Duplicated the issue again. This time I opened the line where it connects to the abs module to the back line on the master cylinder. It unlocked the caliper. Would that suggest its the master cylinder?

 

I can't say I've had personal experience with this particular issue. But, from what I have read on here, it sounds like you have the same problem as the other poster. If it were me, I think I'd go ahead and get a OE master cylinder and give it a shot before I took it in to a shop or dealer where they might start at square one replacing expensive parts like the ABS.

 

Talked to the PO again about what was replaced. The master cylinder was done months before the issue started. I took that master cylinder back Autozone and got a free replacement, just to try. Sure enough, the issue stopped. I need to bleed the brakes again but so far so good....