The mechanism of a garage door cable is more complicated than one might think, and repair is usually a professional job. The cable supports the entire 300-pound weight of the garage door, placing it under constant tension. Several things can go wrong with the cable, each posing significant safety risks that put this type of repair outside the capabilities of the DIY enthusiast:
- The lift cable rides inside a groove on the drum at the top corner of the door. Rough treatment such as slamming the door shut can make the cable slip out of this groove.
- Since the cables support the full weight of the door, they are under high tension and will break after years of wear. The door has two cables, and when one breaks, all the tension is transferred to the other one.
- Inner strands on the cable may become frayed, though the outer part still looks good. The owner is usually mystified, since the cable gets slack and twisted but still seems fine to visual inspection. Without the all-important tension, the garage door stops functioning properly.
Each of these problems creates a serious safety risk. When a garage door cable breaks or slips out of its groove, the door can drop suddenly and cause injury to anyone standing underneath it. When a garage door is stuck open, people and objects should be kept out from under it.
When a garage door cable breaks, the end is a jagged piece of sharp metal that can cause severe injury. Breaking causes a sudden release of tension, and the end of the cable can slash out with a whip-like motion.
Aside from the risk of personal injury, a misaligned garage door can cause further damage to itself. If someone tries to open a garage door with one broken cable, the door can get pulled sideways and hung.
This is a more difficult repair job than a simple misaligned cable, and it will cost more. Fraying of the cable strands also throws the door out of alignment and poses a similar risk of greater damage.
Considering the risks to the door and the homeowner, it’s a good idea to leave garage door repairs to trained personnel. The owner should periodically lubricate and inspect the cable for signs of wear or slackness. When any appear, the door should not be used until a professional repair service has made repairs.