I reviewed the supplied instructions. I moved the brackets that interfered with the replacement rollers. I needed to bend slightly the front portion of the lower rail to get to the nut holding the old roller. After removing the nut, I was able to easily remove the old roller and put the new one in place. Tightening the nut to spec I then carefully bent the lower rail end back in place. Repeating the processing on the other side I was able to complete the job in about a half an hour. The new parts fit perfectly.