Hello,

I need to square up a panel on a very old, heavy, metal sliding glass door. I understand that there should be a screw at the bottom of each side holding the panel in place, with a small hole underneath for inserting a screwdriver to adjust wheel height. On this door, that lower hole has a screw in it on both sides. Is this just covering the hole to keep dirt out, or do older doors have a different system altogether? I don't want to remove that screw if it's going to mess something up in my friend's rented condo...

 

The standard advice when the word "rental" is part of the question is that its not your business to be doing repairs on someone elses' property.

That being said, since we can't see your door or rollers without a picture, we would just be guessing. On some rollers, the door is adjusted with a LONG #3 phillips screwdriver inserted under the door, just above and parallel to the track. If there is a screw on each side, I would not be surprised if those 2 screws secure the roller to the door.

Other doors will have a screw COVER... and when that cover is removed, it allows you access to the adjustment screw on the roller body.