The garage door opener motor consists of the motor assembly and the motor gear. The motor assembly is a grey cylinder, mounted inside the unit’s frame. The motor gear is a white-toothed wheel, which is mounted on a long metallic piece called the sprocket shaft. You may or may not need to replace the motor gear and sprocket, however, this article will include the replacement of these parts too, just in case.
Step 1: Buying the Replacement Kit
Purchase the replacement kit, depending on whether or not you are replacing the motor gear along with the motor assembly. Also, consider the specifications of the new motor that you are buying. A garage with space for two cars usually needs a motor with ½ horsepower.
Step 2: Disconnecting the Motor Unit
Let the garage door be in a closed position. Make sure that the unit’s power is turned off and cable is removed from the socket. Remove any connections between the trolley and the motor unit by unplugging the associated cables. Loosen the chain by wrenching the tension nut mounted on top of the trolley. Now, remove the cap that holds the chain on top of the motor unit, and then dismantle the chain by taking it off the unit’s sprocket. Remove the unit’s cover by unscrewing the 3 or 4 screws that hold it in place.
Step 3: Dismantling the Old Motor
Take note of the white wheel inside, that is your motor gear, and see how it is connected to the unit. There will be a plastic retaining clip holding it in place, which needs to be removed. Use the manual to identify the limit switch assembly, and by pushing the brackets on its sides, dislodge it too. Disconnect the RPM sensor from where it is held with the wire, and move it out of the way. You will now clearly see where the motor assembly is connected to a capacitor with three wires- red, blue and white. Remove these wires from the motor and mark the terminals for future reference. Locate the four screws with which the motor assembly is attached to the opener’s frame and unscrew them. Dislodge the old motor assembly from the unit. Now, remove the three screws that hold the sprocket in place. You can now remove the motor gear and sprocket assembly from the unit too.
Step 4: Installing the New Motor
Using the three screws you had unscrewed earlier, attach the new motor gear and sprocket to the unit. Now, attach the new motor assembly to the unit using the four screws that the old one was attached to. Attach this to the capacitor using the red, blue and white wires. Place the limit switch assembly back in place followed by the RPM sensor. Reconnect all the previously disconnected wires and set everything back in place. Finally, put the motor unit’s cover back on and screw it in place. Lube all the moving parts within the motor, such as the gear, before you switch the unit on.