closet sliding door keeps falling off track
Is it falling off b/c there is no stopper or is the wheel the wrong size for the track?
Get a ladder and look at the track. Use a small tack hammer and tap inward in any area that looks like it has widened. (Basically pinch the track lips closer together.)
Some possible repairs
Try this video.
A likely source of the problem is the wheels. They do wear out over time. A bit good news though...home improvement centers normally carry several types and they’re inexpensive. Make sure to carry yours with you because there are so many types. You can also get them online on Amazon and other sites.
You need to rais the bottom screw up so the door is up in the air more you need to take the door off there is a long screw that the door balences on with. Metal piece on the end screw that so it comes out some then put the door back the piece T the top will push down there is a spring