Review on 🔧 Liftmaster/Chamberlain/Sentex 41A2817 Gear Kit: Enhance Garage Door Performance by Ben Jacobson

We had two old (early 2000's) 1/2 HP Craftsman openers in our house. About six months after we moved in, a door opener stopped working. The motor ran but the door didn't move. I assumed it was a typical Chamberlain/LiftMaster/Craftsman nylon gear box failure and when I opened the unit up, a mountain of white nylon shavings confirmed my suspicions. As most other reviewers have pointed out, it's not the easiest job in the world, but it's not brain surgery either. With a little patience and a few common hand tools, you'll have your knife back up and running in about an hour. Very carefully remove the plastic e-clip and door position gear from the bottom of the shaft. The kit does not include replacement parts for these parts. The clamp looks a little wobbly. Read the instructions carefully. Above all, start with the door closed and the opener standing in the fully closed position. This helps a lot when readjusting the opener at the end of the job (which isn't difficult at all). The instructions recommend removing the motor first. I found it unnecessary. I was able to fit a small ratchet and 5/16" socket onto all three bolts that attach the driveshaft flange to the top of the opener. This can save you a few minutes of work and a little trouble, especially when working with stairs. As stated in the instructions, the worm wheel on the motor shaft does not usually need to be replaced as it is not the weak link. Mine looked like new. Problem. The kit is designed to fit many models and not every model uses the same parts. I ended up using a pinion gear, a C-clamp, a drive shaft bushing, a wave washer and two more drive shaft washers. My bushing was very stiff which I believe was the cause of the failure of the nylon gear. I teflon coated the driveshaft bearing surface and the inside of the new bushing and the assembly turned very freely. Loosen the pins on both sides of the gear. Turning them off isn't that hard, but keeping everything in place can be nice. I snapped the driveshaft into two 2x4 pieces, with the gear between the 2x4s, and threaded a drywall screw through a third, unused hole (you'll see what I'm talking about) in the driveshaft. This worked great to keep the shaft stable and keep the roller pins vertical. Line up your punch, a few hammer hits and you're done. I used new roller pins. Calculating the opening time seems to be the most difficult step for some people. However, it is easy. A double-sided metal contact is attached to the threaded shaft, which rotates perpendicular to the chain drive shaft. When it reaches a limit of its travel, it hits a metal contact that tells the control board that the door is closed. Reaching the opposite path, he encounters another metal contact that tells the control board that the door is open. These two contacts are on threaded rods rotated by screws accessible through the share body for the upper and lower end stops. As long as you start with the door closed, the chain carriage engaged, and the opener in the "fully closed" position (i.e. the double-sided metal contact is just touching the lower limit contact), you probably don't need to change this thing. If something is wrong (e.g. the opener got stuck halfway and you pulled and closed the manual latch), just put it back in place. Close the door, push the cart and connect it to the door, THEN put the chain back and adjust the chain tension. You can run the opener with the chain removed to bring it to the "fully closed" position. The guide explains how to do this by observing the direction of rotation of the sprocket to see if the blade opens or closes. I didn't have a remote handy since I use Homelink, so I plugged in the opener, pushed the button on the wall, and then pushed it again. If the opener just stopped, I knew it was moving up. If it's turned over, you'll know it's moved down (and so you'll have to restart the opener after it's stopped to return to the fully closed position). Disconnect the blade, reinstall the chain, adjust the tension and you have very little work to do to set the up/down travel limits. Congratulations, you just saved $200 and eliminated the hassle of installing a new opener! Don't forget to properly lubricate the chain, check the tension after opening and closing the door, and keep an eye on your door rollers and springs in case a mechanical failure was responsible for your mechanism failing.