I know this is an old thread but the problem persists. I posted on another thread that there are two likely problems if brake drag develops in the Theta platform cars ‘10 or older. One is the brake hoses get squeezed by rusty brackets and the other is tha the master cylinder goes bad and leaks into the brake booster. The the booster malfunctions and both need to be replaced. So here’s what I’ve learned. If your brakes seize intermittently it’s probably the brake lines (hoses) problem. If it’s constant it’s probably the master cylinder/booster problem. Okay, assuming you find that problem and fix it, problem two can, but not always rear it’s disgusting head. Sometimes the new brake booster/master cylinder combo, even if they are ACDELCO both, can be slightly out of adjustment which will result in, BINGO, the same siezing problem. This is what sends people off the deep end. I had to remove the new master cylinder and screw on the pushrod inside the booster. Now, I compared the new and old adjustment of the push rod and they were the same. Yet, I had to turn the rod in about three turns. You have to clamp the base of the rod and turn the insert in with a socket. This cured my problem including the Stabiltrak/traction Control lights. This whoordeal took me over a week to figure out and since my original problem was the hoses, it kind of aggravates me that GM hasn’t owned up to this issue. I don’t even care if they waited till my (or your) car went out of warranty before contacting us because it still would have been better to pay than to go crazy chasing the problem. Hope this post helps. I didn’t explain some technical stuff but I wanted to focus on clearing up the confusion.