Addressing Sagging Chains or Belts in Liftmaster/Craftsman Openers

Common Issue with Garage Door Openers

Q: The chain or belt on my Liftmaster/Craftsman opener is sagging, but still works. Should I do something?

A: This is a common problem, especially with the do-it-yourself home install openers that you will find at retail hardware stores like Lowe’s and Home Depot. First, someone who has never installed a garage door opener may tend to tighten the chain or belt way too tight during installation.

Understanding the Root Cause

When this happens, it puts an extra amount of pressure on the chain sprocket or the belt sprocket. After about 3 to 5 years of this overload of pressure, the stem that the sprocket is attached to can shear off, similar to how a metal lathe operates. This leads to the sprocket moving forward, causing the belt or chain to sag over time.

Avoiding Further Damage

The worst thing you could do if you have this problem is to tighten the chain or belt even more. This action only accelerates the deterioration of the sprocket. Inexperienced garage door technicians may inadvertently do this due to their lack of proper installation knowledge. If you encounter this issue, it’s likely that you will need to replace the gear and sprocket kit inside your garage door opener.

Importance of Professional Installation

This maintenance issue is quite common with all garage door openers, whether chain or belt-driven. When a technician installs the new gear and sprocket, ensure they do not tighten it too much. Ideally, the gear and sprocket should last anywhere from 10 to 15 years without any issues when installed properly.

DIY Fix: Proceed with Caution

If you decide to find the gear and sprocket kit online and attempt to fix the problem yourself, be sure you are mechanically inclined and knowledgeable about appliance repairs. Improper installation can lead to a host of additional problems, so proceed with caution.

Cost Considerations for Repairs

As a point of reference, I usually charge about $179 plus tax to fix this problem on a garage door opener. Keep in mind that belt drive gear and sprocket kits can cost a little more, so it’s prudent to be aware of that when considering your options.

Frequently Asked Questions

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We receive many calls involving the safety eyes preventing the garage door from closing due to the safety eyes malfunctioning or simply being out of alignment. If your garage door opens fine, but will not close using the wall console, then this could be a safety eye issue. If the opener light flashes and/or the motor makes a clicking sound, this is a warning that you have a safety eye issue. You can begin by looking at the safety eyes themselves. You should see a steady light on both of the safety eyes. If one of the lights is flashing then you may just need to simply align the eyes properly. This is done by physically moving/adjusting the safety eyes until you have both safety eyes with a solid light showing.

If both safety eyes are showing a solid light, then you may have malfunctioning safety eyes.

A simple test is to press and hold the wall console to close the door. If the garage door closes while holding the wall console button, then you probably have a safety eye issue. 

We offer a full line of commercial garage door openers to fit the needs of the customer. For smaller commercial sectional garage doors we recommend using the Liftmaster 8900W these operators are rated for 14 feet maximum height and 300lbs total weight. For rolling steel doors we recommend the 8950W for doors up to 12 feet maximum height and maximum weight of 850lbs.

For large sectional commercial doors we recommend the Liftmaster J or H. These are equipped with MyQ for automated opener control and are equipped with a soft start/stop feature.

The Liftmaster J, jackshaft opener is available in ⅓, ½, ¾ and 1 horse power. The horse power needed is based on the total square footage of the sectional door it will be installed on.

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