Sorry, the web browser you're using is not supported by this website.

Please use Google Chrome, Firefox, Safari, or another browser to access homex.com. Thank you.

Skip to main content

We use cookies to enhance your experience. For details on how we use cookies, collect data, & how to manage your consent please see our Cookie Policy & Privacy Policy.

How do I replace a Drive Chain in a Garage Door Opener?

Follow these steps to fix your issue:

  1. Disconnect power

    The power cord and motor unit of the garage door opener can be accessed using a step ladder. The garage door opener needs to be unplugged.

  2. Take the garage door opener down

    To release the trolley from the garage door, you have to pull the emergency release rope. If the garage door isn't already closed, close it. The outer trolley has a ring on it that connects to the straight door arm. Pull out the clevis pin while supporting the straight arm to open the garage door. Take the straight and curved arms out of the garage door. If necessary use a helpers. To access the wall control and safety sensor wires, open the light cover. Take a picture of the wires that connect the wall control to the motor unit. When you connect the wires you will see the photo. The wall control and safety sensor wires need to be unplugged from the motor unit. The light cover must be closed. The motor unit is secured with nuts, bolts, and lock washers. Support the motor unit with one hand as you remove the last bolt. Take the motor unit down and put it on top of the step ladder. The motor unit can be lowered from the step ladder. You need to move your ladder by the garage door to remove the rail. The clevis pin has a fastening ring. Pull the clevis pin out of the rail with one hand and support the rail with the other. Lower the rail to the floor of the garage. To avoid scratching a decorative garage door, remove the nuts, bolts and washers from the curved arm and rest it against the door when the garage door is disconnected from the outer trolley. When pulling the garage door opener, you may want to have a helpers assistance.

  3. Remove the chain and cable assembly

    The inner trolley should be moved away from the outer trolley. The inner trolley can be reinstalled in the same place after the chain and cable assembly is replaced if you mark the rail. The threaded shaft has an outer nut. Take the threaded shaft out of the trolley. The chain must be removed from the motor unit sprocket. Remove the master link clip-on spring from the trolley. The master link bar and master link cap need to be removed. The lock washer and idler pulley nut need to be removed. Pull out the idler pulley bolt and slide it out of the rail window. The chain cable needs to be removed from the rail window. Remove the master link clip-on spring, master link cap and master link bar to remove the trolley threaded shaft from the chain. The chain and cable should be removed.

  4. Install the new chain and cable assembly

    Next to the rail, lay the new chain and cable assembly. Attach the end of the chain cable to the rail window. If the idler pulley center hole is dry, add general-purpose grease to it. The pulley should be inserted into the rail window behind the chain cable. Remove the idler pulley bolt and tighten it with the lock washer and nut. The idler pulley needs to spin freely after being tightened. Push the pins of the master link bar up through the cable link and trolley slot to connect the chain cable to the retaining slot. The master link cap should be pushed over the master link bar pins. Take the clip-on spring over the master link cap and place it on the pin notch. The inner trolley should be positioned on the rail. Make sure not to twist the chain by aligning the rest of the chain and cable along the rail and threading the chain through the chain spreader and around the motor sprocket. Push the pins of the master link bar up through the threaded shaft mounting hole and the end link of the new chain to connect the trolley threaded shaft to the new chain. The master link cap should be pushed over the master link bar pins. Take the clip-on spring over the master link cap and place it on the pin notch. The trolley threaded shaft has an inner lock washer on it. The trolley should be inserted through the hole in the trolley. Attach tension to the trolley with channel lock pliers. Place the lock washer on the trolley threaded shaft and thread the outer nut onto the threaded shaft. It's easier to thread the outer nut onto the trolley shaft if you push the inner trolley toward the threaded trolley shaft.

  5. Tighten the chain

    Tighten the outer nut to pull the trolley threaded shaft into the trolley, then tighten the chain until the chain is 0.25-inch above the base of the rail. To get the adjustment, tighten the inner nut against the trolley.

  6. Reinstall the garage door opener

    The rail end should be connected to the brackets using a clevis pin and ring. Set the motor unit on top of the step ladder when you position the ladder under the ceiling. Use nuts, bolts and lock washers to put the motor unit back in the ceiling. The wall control and safety sensor terminals can be accessed by opening the light cover. Attach the wall control and safety sensor wires to the motor unit using your photo as reference. The light cover must be closed. Attach the straight door arm to the outer trolley by using the clevis pin and ring. The trolley must be re-engaged. If you disconnected the curved door arm from the straight door arm while freeing the garage door from the outer trolley, you should use the bolts, lock washers and nut.

  7. Reconnect electrical power

    The garage door opener should be plugged in.

  8. Adjust the travel limits

    To check upper and lower travel limits, run the garage door opener. If the garage door does not completely close, adjust the down travel and cycle the door open and closed to see if the adjustment is right. Continue adjusting the travel until the door closes completely. If the door doesn't open completely, adjust up travel the same way. The motor of the garage door opener can become overheated and shut off if it is continually operated. Allow the motor to cool and then adjust it.

Time required:

60 minutes.

You would need the following tools:

general-purpose grease, phillips screwdriver, slot screwdriver, socket wrench set, step ladder, work gloves.

Let's Get It Fixed!

HomeX virtual experts will assess your issue (for free!) and can resolve simple problems.

What Did You Think of This Article?

What Did You Think of This Article?

Shop Recommended ProductsShop HomeX Recommended Products