Compressor making excessive noise

One front roller was flat on one side. Decided to replace all rollers at same time. Placed shims under unit and removed mounting screws for one front and one rear roller. With new rollers in place, I was able to level the refrigerator side to side, but unable to do so, front to back. Left the new front roller in place and reinstalled the old rear roller. Have decided to replace refrigeratorin the near future. This is one of my few repair failures!