Look at the bottom leaf of the hinge you are replacing. The hinges are numbered 1 through 3 on most residential garage doors. The hinges in the center of the panels are No. 1 hinges. They have a single sleeve. The end hinge connecting the bottom section to the second section is usually a 1. The end hinge connecting the second section to the third section is a 2, and the next end hinge is a 3. Purchase replacement hinges at a home improvement center.
Close the door and engage the door lock. If you have a garage door opener, close the door using the wall button station for the opener. Position a stepladder under the garage door opener motor and unplug the opener power cord from the ceiling outlet. This will prevent someone from accidentally opening the garage door with a remote while you are working.
Remove the screws securing the old hinge to the door with a socket wrench if your garage door is steel. Wooden garage doors use carriage bolts that insert through the door from the outside. Remove the nuts securing the hinge to the carriage bolt with a socket wrench. Tap the end of the carriage bolt with a hammer until the end is flush with the hinge.
Pull the hinge away from the door, bringing the roller with the hinge. Pull the roller out of the old hinge, and insert the roller into the sleeve of the new hinge. Rollers have a stem that goes into the hinge. Hinges with numbers above 1 have two sleeves. Insert the roller into the sleeve that extends farthest from the hinge.
Position the roller inside the door track, and line up the hinge mounting holes with the mounting holes on the door. Secure the hinge with the self-tapping screws and a socket wrench if your door is steel. For wooden doors, go outside and tap the upper and lower carriage bolt back through the door. There are four bolts that secure the hinge. Go back inside and position the roller in the track. Angle the hinge over the threads on the carriage bolts until the hinge is flush against the door. Thread the retaining nuts over the carriage bolts. Tap the remaining two bolts through the door and hinge. Secure the hinge with the securing nuts.
Plug the opener power cord back into the ceiling outlet, if your door uses an opener. Unlock the door lock if your door is manually operated.