Brake Master Cylinder problems of the 2013 Chevrolet Suburban

Have replaced calipers 3 times since August 2018. Started with squealing of brakes and then taking to mechanic to find that caliper was "frozen" and eating up the brake pads. The abs pump is not releasing appropriately and causing the brakes to remain in a braking mode while driving. It is not both sides at the same time. It has alternated sides so the master cylinder was ruled out as an issue. Inner and outer tie rods ends were replaced first, and then the first set of calipers. Then brake hoses, pads and rotors were also replaced. At that point, the squealing happened after about two weeks of driving and we found it was a caliper sticking. Thinking that it was a faulty replacement, it was replaced and did fine. Two weeks later the same happened with the other side. This has happened another time since the first set was replaced. At this point my mechanic had figured out that the abs pump was what was causing the issue and because it was somewhat intermittent, it didn't trigger a code in the vehicle. He was able to do testing that showed failure on the side the caliper was not releasing on and then after about 5 minutes, it released, he retested and it passed. He called his oem supplier who then told him this was a "known issue" and that there were only 5 of the pumps available nationwide and all were spoken for. About a week later, the rep let him know that the part was in production with a ship date of Dec. 3rd 2018.