Safety: Garage doors are heavy and spring/cable systems can be under significant tension. Do not loosen or disassemble high-tension hardware unless you are qualified to do so.
Signs of Cable Trouble
Visible fraying, a cable hanging loose near the track, uneven lifting, or one side of the door sitting lower than the other can indicate a cable or drum problem.
Cable and Spring Systems Work Together
Cable tension is connected to the spring system, so a cable issue may also require checking springs, drums, bottom brackets, and door balance.
Avoid Handling Tensioned Hardware
Bottom brackets and lift cables can be associated with significant spring tension. Avoid loosening hardware you are not trained to service.