I have a 1999 Silverado. recently changed rotors and this seems where my problems began. Guy at Pep Boys told me there was two different diameters (outside diameter of total rotor)so I got the one with 3:73 rear end. I have never been asked this before?? Would the drum portion be a different size? Put them on and cant get them to hold the truck. Adjusted the star wheel out as far as it will go and even broke them. Shoes now rub rotor on turns. Shoes are almost like new and have replaced both back cables. Adjustment under drivers side is tightened all the way. Put shoe inside drum and had a heavy 1/16 a side. Could I have the wrong rotor? Could the drum part be a different size in different years or models? Tired of wasting money and time. Never had to adjust parking brake before because I didn't want the rust ridge preventing it from coming off but it still worked? Im ready to go to Napa and get rotors to mic and see what size they are? Does anyone know what the diameter of the drum portion is? GOING CRAZY OVER THIS!!!