How to Replace Steel Cables for a Garage Door

Unplug the power cord of your garage door opener from the electrical outlet. Slide the safety clip out of the end of the pin that secures the garage door arm to the door opener. Remove the pin and let the arm hang down. Skip this step if your door is manually-operated.

Raise the garage door manually all the way up. Clamp a pair of locking pliers to the garage door track in front of the second set of rollers at the bottom of the door. Do this for each side of the door. Note that this will keep the door from lowering unintentionally when the springs are disconnected.

Locate the cable attachment point at the top of each corner of the garage door opening. Untie the cables from each of the brackets.

Ensure that the garage door springs are loose and not under tension. Note that the spring should move easily. Unhook the S-hook from the end of the one of the springs from its bracket at the top of the garage door opening. Let the spring hang down.

Remove the retaining bolts from the bottom roller on the garage door -- which doubles as an attachment point for the opposite end of the cable -- with a socket and ratchet wrench. Slide the roller out of the track and remove it. Let the bottom of the door hang down.

Unhook the cable from the roller bracket. Pull the cable from the spring and discard it. Hook a new cable to the hole in the bracket. Insert the roller into the door track. Lift up on the bottom of the door and replace the retaining bolts in the roller bracket.

Thread the cable through the spring until it protrudes from the opposite end. Hook the S-hook on the spring back into the bracket at the top of the garage door opening to secure the spring in place. Thread the end of the cable through the hole in the bracket that the previous cable was attached to. Pull the cable tight and tie the end of it to secure it to the bracket.

Repeat the process to replace the remaining cable. Reconnect the garage door arm to the door opening if applicable. Remove the locking pliers from the door tracks. Plug in the opener's power cord if applicable.