I bought a truck from Glenway Chevrolet and they handed me the 100 something point check they supposedly do to them. called the GM certified check. the rear brakes was checked off. but when I pulled the drum off 2 weeks after I bought it the spring hardware was rusted in half and the pads were basically scraping the drum. there's no way in hell those were checked. I never went back for it because the parts cost me a whopping $30. but still, certified checked eh... that's alright because I made them put a new thermostat in it and give me a new key with a new keyfob.