Usually, if a garage door spring ends up getting broken, you will likely not notice it until you try to open the door using your garage door remote. Contrary to popular belief, entire weight of your garage door is supported by these springs rather than the garage door opener. Garage door manufacturers stretch or wind these springs under pressure, but loosen and tighten as the garage door is opened and closed. So, it is not unusual for one of those springs to break and to avoid garage door opener repair, it is best to call a professional, but you can still attempt to repair it yourself.
Step 1: You can manually lift the door by pulling red-colored emergency release cord at the top. You may need help in lifting the door and get your car out.
Step 2: Identify whether the broken spring is an extension or torsion spring so you can buy a new one. Even if all of the garage door springs have not broken it is best to replace all of them because they are installed at the same time and they may also end up breaking soon enough. If the springs are located on both sides above the upper tracks, then they are extension springs, so you can proceed to removing them.
Step 3: If your garage door is equipped with an electric opener, disconnect the wires between it and the switch, and unplug it. Disconnect the garage door’s support arm after getting a helper to pull the release cord and hold it steady so you may remove the bolts securing the power unit and trolley.
Step 4: Remove the bolts and all other hardware holding the power unit, supporting it. Before the springs can be disassembled, you will have to attach clamps to both sides of the tracks after lifting the door, so that it dos not roll down once you remove the springs.
Step 5: Both the springs will have to be taped or tied to the track so that the lift cables can be removed from both sides of the lower brackets. You can then disassemble the pulley and spring assemblies so you can remove the springs.
Step 6: It is best if you lower the garage door down as well, in order to avoid an accident and to be able to conveniently and safely replace the springs.
Keep in mind that you should remove all of the springs and replace them. If you only replace the broken spring and use it with an old spring, your garage door will be thrown off balance and the motor of your garage door opener will end up getting burned out. So, avoid this or you will end up requiring garage door opener repair as well. Moreover, if you are certain that your garage door has torsion springs; you should not even bother replacing it on your own.