Troubleshoot garage doors by identifying the problem and addressing the cause. For example, if the door has jammed, look at the track to see if it's bent. If it's not, it's likely that the extension spring cable has broken or its pulleys are worn. Use lubricants to maintain the door.
About once a year, spray WD-40 or another penetrating solvent on the hinges, latches, roller tracks and rollers of a garage door. An environmentally friendlier solution is a citrus-based solvent. Also apply the lubricant to the pulleys to the bearings on torsion-spring openers and the pulleys on extension-spring openers. Wipe some oil on the torsion spring if it shows signs of rust. Apply lubricant to the drive screw or chain. If the weather stripping grabs the sides of the doors, adjust or replace as needed.
Some of the most common problems affecting garage doors include a door that refuses to open, won't close all the way, sits at an angle, or keeps closing partway and then opening again. Many times, the torsion spring cable or the extension spring cable causes the problem. The pulleys that the cables navigate to operate the door can also be problematic. Replacing these cables or the springs along them solves many garage door problems without having to install a new door.