My son is trying to repair my garage door. (I'd rather not have to buy a new one.) The bottom roller on one side was missing when we bought this house in 1974 and that has never been a problem. However, my son and brother-in-law have now determined that the missing roller is part of the current problem. The track is only 1 1/2 inches and the smallest rollers I've been able to find are for 2-inch tracks. Any suggestions???