I had a 1977 chevy van. I did all the repairs myself. Disc front drums on the back. I always changed front pads at about 20,000 miles and at 60,000 miles when I did I had to press on the brakes harder. They started this at about 50,000. So I took off the front rotors got my brake lathe out and turned the front. Made a big difference. So I did the rear after to see if that would help to. Really didn't notice much difference on the stopping by doing the shoes on the back and turning the drums and make a back cut deeper on the drums so you can take off the drums more easy. I hate crawling under the back to a knock the plug out to back off the adjustment screw. why the undercut if your doing drums. What was wrong with the front disk was that the cast iron work harden after so long. They look perfect just to hard of a surface for the pads to dig in.