Garage door cables are used in both the extension spring and torsion spring systems. As with all other garage door parts, one must always replace the parts symmetrically when repairing a garage door.
Garage door cables
In an extension spring garage door system, the cables wind around pulley wheels.
Garage door cable around pulley wheel
  In the torsion spring system, the cables wind around cable drums.
Garage door cables around cable drums

Cable Breakages

Garage door cables can break for a number of reasons. These include:
  • Normal wear and tear or aging
  • The garage door is hit by a car
  • Lace of regular maintenance
  • There is a jam in the track while the door is opening or closing
  • Vigorous opening and closing of the garage door
The simple way to check the state of your cables is to inspect them. If there is any fraying of the cable or it looks worn in any way, it is best to replace it before it snaps altogether and causes damage or injury. Even if just one cable breaks, you need to replace both of them. The cables stretch over time but need to be the same length for good functioning of the garage door. Furthermore, they must both have been under the same amount of stress – using one new one together with one old will put things off balance. The chances of your second cable breaking fairly soon after the replacement of the first cable is high.  

Cable Drum Slip

Broken garage door cable
When there is a torsion garage door system, the cables can come off the cable drums. This is called “cable drum slip” and can be caused by various issues:
  • If the door closes and hits something and and does not move back up again. It can rest on the object and the cable on one of the sides will become slack.
  • Where there is only one torsion spring and it breaks. The door will come crashing down, cable tension will be lost and the cable will unwind from the cable drum.
  • If the tension in the torsion spring is incorrect. Over-tensioned and the cables will jump of the cable drums; under-tensioned and the cables will unwind.
  • Wrong cable and cable drum sizes. The cable must be the correct diameter for the weight of the door and the cable drum must be the correct size for the height of the door.

Cable and Pulley Wheel Problems

In the case of cables that run around pulley wheels, the cable can come off the pulley without breaking. Reasons for this include: Imbalance or uneven weight distribution in the door
  • Age
  • Forcibly slamming the door closed
  • Problems with the springs or spring tension.
  • Lack of maintenance of your garage door.