Five things that put a roller outside the track
A sectional door stays in its tracks while both sides lift evenly, the rollers are sound, and the two tracks are straight and the right distance apart. Lose any one of those and a roller can come out, usually at the curve where the vertical track meets the horizontal one.
- Something hit the door or the track: a car backing out before the door is fully up, or a bumper or snowblower against the bottom of a track. A dent the roller cannot pass makes the door bind there, and a hard enough hit pushes rollers straight out.
- A lift cable snapped or came off its drum, so one side of the door stopped lifting and the door twisted in the opening. That side is a cable repair as well.
- Worn or broken rollers: a cracked wheel or a bent stem lets the roller ride up the edge of the track and out. See roller replacement.
- Loose track brackets, or a track that has spread or bent, so the gap between the tracks is wider than the door. See track repair.
- Something in the track: a pebble, a tool, ice or a toy jams a roller, and the opener pulls the door past it.