The locking mechanism to keep the rail in place on my Master View (8x10) is not working. The knob at the front right pushes a very thin rod up against the rail to keep it in place, and I am guessing that there was some kind of pad there which pressed up against the rail to keep it from moving. If there was, it is no longer there. Does anyone know what would fit on the end of that rod, or does anyone have a repair manual? There was a thread a few years ago in which the link to a manual was posted, but the link no longer works.