Can I replace a torsion spring myself?

You can replace a torsion spring yourself, but it is one of the riskiest DIY home repairs and is responsible for thousands of emergency room visits each year. The spring sits above the door under enormous tension and has to be unwound and rewound by hand using two correctly sized winding bars. A slipped bar or wrong-size spring can launch a metal rod across the garage with bone-breaking force. If you decide to do it, weigh the door first to size the spring correctly, buy matching replacement springs and proper winding bars (never use screwdrivers), unplug the opener, clamp the door closed, and follow a complete video tutorial. Otherwise, this is the job to leave to a pro.