On the tractor hauler propulsion unit . I have not done anything with the brakes in the five years and 60,000 miles we have owned it so I don?t feel to bad. Twisted one lug bolt off and had torch the stud and lug nut off an another one heated up another one with torch and it came off that?s when I knew this job was going to be a bugger Ended up replacing both front calipers and pads went to bleed the brakes and blew a rubber line on the front so I decided to go ahead and replace all the rubber lines on the truck well the rear steel lines wouldn?t come out of the rubber line that tees to the left and right side so ended up replacing both steel lines on the back as well