Sears, Chamberlain, Liftmaster & Master Mechanic Garage Door openers

[Mark42]

Just a heads up, this might save you a few bucks and some repair time:<br /><br />Chamberlain, Liftmaster, Sears Craftsman, Master Mechanic and Garage Master chain drive garage door openers manufactured from 1984 to the present use a worm gear drive between the motor and the shaft to drive the sprocket. The drive and driven gears are a plastic, probably nylon. Mine just failed as the worm gear shreadded the driven gear.<br /><br />My opener is the Sears branded opener that has been in servie since 1998. It's 1/2 hp and opens a heavy wood double door (16 x7). I keep the springs properly tensioned to relieve stress on the opener, but nonetheless, the gears stripped out. If there was a label indicating that the gears should be greased every year or so it probably would still be in service.<br /><br />I ordered the replacement part kit, with shipping cost $44. Will probably take me better part of an afternoon to remove and replace. Doesn't look hard to do at all, just unnecessary. <br /><br />So you might want to remove the 4 sheet metal screws holding the cover on the opener and inspect and grease up those gears. At $44 for the parts, it's well worth taking a few minutes to check it out. <br /><br />Otherwise it has been a trouble free opener. If your opener opens a single bay door it might last longer. But with properly tensioned springs, my double bay door is just as easy to open by hand as a single bay door, so the opener isn't working much harder, if at all. <br /><br />

<br /><br />BTW you can buy just the two gears with new roll pins, but I decided to get the assembly because the bushing the shaft rides on is probably also worn from not being greased. The gear kit is about half the assembly price.

 

[speedwrench]

Re: Sears, Chamberlain, Liftmaster & Master Mechanic Garage Door openers

I am using the same opener on 24' steel door and been thru all this. <br />Good move getting the shaft with the kit.<br />If you have to replace the opener, just replace the head, the old I-beam rail is a lot stiffer than the new square one, and you can brace the old style to keep from flexing with the heavy door. Can't do that with new style. <br />Keep spare gear set, you'll need it with heavy door.<br />Lube door & tracks with WD-40, regular grease collects dust & dirt.<br /><br />Dave

 

[eurolarva]

Re: Sears, Chamberlain, Liftmaster & Master Mechanic Garage Door openers

WD40 really is not a lubricant. A 3 in 1 oil would be better. When taking the garage apart be careful if it does not have end limit switches that stop the movement foreward and aft. The machine may need to be retimed when after you install the worm gear.

 

[nothreat]

Re: Sears, Chamberlain, Liftmaster & Master Mechanic Garage Door openers

I used this kit for a Master Mechanic drive last summer. It was fairly simple and took about 2 hours. I did have to readjust the stop and start points when I reinstalled it. I found the kit in Rochester, Indiana on the Internet for around $34. I first went to Sears and True Value and they told me no kits available - you'll have to replace the drive. Mine was from the early 90's.<br />Not a bad job and saved some money.

 

[ehenry]

Re: Sears, Chamberlain, Liftmaster & Master Mechanic Garage Door openers

Same exact drive I have. Broke on Christmas Eve. Found the kit at the place that installed the door. Real easy to intall, like nothreat says took right at two hours.