A garage door is an inclined plane. It works by balancing the weight of the door against the force of two steel cables that are attached to a spring-loaded pulley at each end of the door. The cables run from one pulley at the top of the door to a pulley at the bottom. When you pull on the cable, it pulls down on a spring-loaded pulley, which makes it easier to lift up on the opposite end. The opposite end is connected to a trolley (a wheel with rollers) that runs along an overhead track.
The purpose of this article is not to describe how a garage door works but rather how to troubleshoot and repair broken cables and springs.
Why garage door cable came off?
If one or both cables have come off their respective drums, or if your garage door cable has snapped or broken, you will need to replace the cable. But if one or both springs have broken, or if your garage door spring has snapped or broken, you will need to replace the springs.
If your garage door is difficult to open and close, this could be due to a number of problems. The following are some of the most common problems associated with garage doors:
Broken Cables: If a cable has come off its drum, it will make opening and closing the door difficult. This is because it’s not possible to lift the door when one side of it is missing a cable. You can usually tell if a cable has come off its drum by looking at the drums at each end of your garage door. Each drum should have two cables wound around it in opposite directions (one clockwise and one counterclockwise). If they’re not there, then you’ve got a problem!
Broken Springs: If one or more springs are broken, you may notice that your garage door gets stuck halfway up when you try to open it. If this happens, you know that one or more springs are broken. (Note: A broken torsion spring will cause your garage door to go down instead of up.)
If your garage door is difficult to open and close, or if it’s just making a lot of noise when it opens and closes, the following things should be checked:
Broken Rollers: If your garage door has metal rollers on the bottom, they can be removed and lubricated with WD-40, which will reduce the amount of noise they make when they move. But if your rollers don’t have metal sleeves on them (like our model in the photo above), then they have probably worn out and need to be replaced. You can usually tell if a roller is worn out by rolling a piece of paper across its surface. If it’s smooth, then the roller is fine; but if there are any dents in the paper.