I am trying to fix a garage door that is binding when it gets about 8 - 10 inches above the ground as it is opening. It will usually continue to open but has stoped completely on occasion. I have cheked the tracks and do not find any unusual rubbing or wear. I noticed the other day that the problem only occured when the door was allowed to go all the way to the ground then raised. When we stopped it on the way down with less than two inches before the floor the door would open without a shutter. Any suggestions?