Exactly the same happened last Friday, on Wednesday dealer did a Brake recall and Friday lost like 95% of my brakes, it took about 300ft to stop it, I almost crash with family in car. Saturday called the dealer, i call Chevrolet Road Assist and tow it there, today they called me and tell me they contact Chevrolet Support and no parts were required so how do they fixed? its a software issue? do they deleted the last software update and restore the previous revision? I often tow my 9K lbs RV, can't imagine what will occur if that happens while towing my RV. after reading all the posts about the vacuum pump and master cylinders issues i don't know what challenges should i do now against GM or the dealer.
Any advice will be much appreciated, i don't trust my car!