On my craftsman 1/2 hp garage door opener connected to our 20 year old garage door, lately it has been getting stuck only about a foot off the ground, the chain is saggin so that when the garage is open the chain scraps against the garage door, it used to be able to open it will a slight push to get it rolling, but now it is just stuck, it opens about a inch then stops, at first we thought is just needed to grease the rails, we used this industrial moly ep grease but that didnt work, now we really need to get it working, please help, AND I COULDNT FIND THE PRODUCT ON THE LIST SO I PUT IT IN THIS CATORGORY!!

It may not be the opener causing the problem.Unhook the opener from the door by pulling on the red disconnect handle. Push the door down or pul;l it up by hand by pushing or pulling on the top center of the door where the opener link hooks to door.See if it moves freely or sticks at the place you described.You could have a door spring problem if the door works ok manually the gear/sprocket in the opener is worn.This is an expensive repair and it might be cheaper to replace the opener.The loose chain could be a sign that the sprocket bearing is worn also.If it is not worn the chain is adjustable at the trolley assembly that slides on the rail.

You will need to tighten the chain and see if the opener closes and opens ok. There are kits you can buy if you need to repair the wormgear inside the motor.