Sliding Glass Door Rollers

It's hard to tell what you need without seeing the actual roller itself, but if I were to guess I would say you had the old "tank tread" roller. This hasn't been made in a long, long time and you won't find an exact match for it. 

I've known some customers who successfully got our 81-023 roller to work as a substitute. The adjustment screw is a little higher but it is the only known solution for this part.

If I'm off-base and you don't have that "tank tread" roller after all, then I will need to see it in order to make a recommendation.