Changing a Garage Door Gear - LiftMaster - Part 1

Princess Four was headed out the garage the other day when the garage door stopped half way down and fell to the ground. I called the local garage door repair man and he said it would be over $100 to fix. I asked him if there was something I could do to make the cost less as I am working on paying for Princess Fours school fees and a graduation present. 

He told me if I took the door opener down and took it in, he could have someone put the new gear in it and he would only charge me for the part which was $75. 

I talked with my good friend Jay who was the one who installed the garage door opener. He told me that I could get a new gear on ebay for $25. 


He also told me that taking the unit down would be much more work than replacing the gear assembly by myself and I could probably instal it myself watching youtube videos. 

He told me how to know which part to order and I found out that all Craftsman and liftMaster units since the mid 80's use the same gear assembly. 
 
Jay also warned me to make sure that I got the CHAIN kit and not the belt kit. Most of the people selling them on ebay were clear as to which models would work but I didn't even look at the model number because I knew my unit was purchased AFTER 1985. 
 
If you purchase it on ebay, beware of shipping costs. The gear may be cheap but you pay lots for shipping. My unit was priced a few dollars more than some others but the shipping was free. 

I ordered the parts on ebay and paid $30 total for parts and shipping. It took about a week to get the part as it went to my sisters as I used her ebay. 


I got the parts and watched four different youtube videos so that I could make sure I understood how to put the new gears in. 

So, I follow the youtube video instructions and get myself ready by getting the tools I would need which consisted of a socket set, screwdriver, wrench and a head flashlight.

One thing they didn't mention on any of the videos was to wear gloves. My hands got black with grease from the chain. So, if you are going to do this, wear gloves. This is by no means a professional blog about this but just my experience so do this at your own risk but if I can do it, most people can.

Most of the videos remind you to unplug the opener but that should be the FIRST thing you do when starting. 

THE SECOND, LOOSEN THE CHAIN! NONE of the videos I watched said anything about loosening the chain before working on the door opener.

I spent a good hour after taking the opener apart and putting the new gear in trying to figure out how to get the chain on the new gear. 

So, I figured I would post about the steps to replace the gear since none of the youtube videos worked for me. In the end, I read the instruction to get it figured out.

I loosened the chain wrong the first time so I thought I would share what I learned so that those looking at this may have an easier job doing it than I had. 

To loosen the chain. There is a long screw on one side of the chain and there is a nut on both sides of the chain. DON'T loosen the nut on the attached side. Loosen the nut on the "open" side. You can see in the picture where the back open side is. The nut on the un-open side of the bar can stay in the same place to let you know where the tension is normally. 


To loosen it, used a wrench or long shaft socket and loosen the chain until it is really loose. 

If you leave the front nut on where it was, it should be fairly easy to tighten it as you just tighten it to the nut when you are tightening it up.


Once the chain is loose, unscrew the cover to the metal cover on the garage door opener. To get the plastic light covers off, push in the black tabs and pull them off. 

Once the light covers are off, and the four screws at the top four corners are off, you can pull it off the sides by pulling away from the opener. There are two screws  on either end that need to be removed as well. 
 
You can see the screw hole just underneath the light bulb a few pictures up. There is one on each end. Once these are unscrewed, the cover will slide off but be careful to not tip it towards you if you are on a ladder as there may be plastic or metal shavings in the cover. 
 
After you get the covers off, there is a little white gear at the bottom. There is a plastic clip that you push off. I show where the white gear is and I show the clip pushed out but you pull it completely out. I am pointing at it in the above picture.

Once that clip is out, the white gear slips off. Once that gear is off, the last step to get the main gear shaft out is to unscrew three screws from the underside.

Before doing this, make sure the chain is OFF the gear. You can see how I put it on the metal in the picture to the right. If you don't hook it onto something, you will have it fall and will have to work to get it back where you need it once the new gear is on. You can use a piece of metal or a zip tie if you need but I had no problem by just hooking it onto that metal piece. 

To remove the gear, two screws are easy enough to get off using a socket on a screwdriver. I am pointing to the two of them in the picture. The third, you have to use a ratchet as it is "inside" the unit looking at it from the other side of the white gear.

Use a 5/16 socket to remove them. Once they are off, you can lift out the old gear and twist it out of the top hole. Be careful with this as well as if you are beneath the unit, there may be metal or plastic shavings that will fall as you pull the unit out. There was also graphite and grease balls there as well and it would be bad to get any of those things in your eyes.   
 
The next two pictures show the removal of the screws that hold the gear shaft in. If you are having trouble finding the screws to remove to get the gear shaft out, you can look at the top of the unit and see where the three screws come through from the inside holding it in place.
 
You can see here how the ratchet is useful as there is not much space to get a hand in to get that screw out otherwise. A wrench could work also.

From the top, my gears looked ok. On some of the Youtube videos, the plastic gears were all chipped up. My gears looked like the new one until I started getting it out. Then, the top showed some breakage and if you look at the old verses the new, you can see where the top metal gear has stripped from the shaft.  


I was impressed at what good shape the plastic gear was in. I didn't see any wear on it. Just below the metal gear was broken. Even the little plastic white gear that you remove at the beginning was still in good shape. 

Jay did say to replace everything including the worm assembly since I was up there anyway but after looking at everything, it all looked good. I saved the parts in case I needed them but just replaced the gear assembly. Tomorrow, I will show how I put it back together...