Garage Door Extension Springs

 The hardware setup you see depicted below is a standard set-up most likely with p-728 extension springs. If you have a standard one piece plywood and 2x4 construction most likely this is what you will use. If your door is a single car you will probably only use one spring on each side. 

 Note: The extension springs in your garage are labeled with one of three sizes, p728, p528 or p328. When you purchase your springs you can just order the same ones and in stall them... Some times the label has worn off in this case just note that 728's are slightly wider than your thumb, 528's are about as wide as a silver dollar, and 328's (rare) are about 3" in diameter...(rough guess) most likely you are working with p728's.

Go her for a detailed guide on garage door extension spring repair. You want to make sure that you have the right spring for the job so that your garage door is fully balanced. It is a good idea to keep a nice coat of lubricant or motor oil on your garage door extension spring to ward off corrosion.