Is your window operator nylon wheel popping out of the window track? If this is problem you are having, we might have an easy solution. First of all this problem is usually caused by “Sash Sag”, poor craftsmanship, or the rotting of the window. Sash Sag is when the Sash (the glass part) of the window starts dropping. Glass is a liquid and moves over time, have you ever looked through a really old window? Poor craftsmanship, is basically poor construction. And the last item is a rotting sill or the material under the sill. Anyways, the easy solution is to shim the outside edge of the window operators rectangular base. You want to put upward pressure on the window track. You can use anything you would like, but small washers work really well. See the diagram below to see were to put the washers. You can see all of the available Truth Window Operators on our website.