Help finding a matching roller

Hello! We had several sliding glass doors replaced about 12 years ago. One of the doors was always ihard to open. The installer adjusted it at one point, but it didn't really help. Now the door it just about impossible to open and close. My husband thinks the roller was faulty. Unfortunately, the company who installed the patio door has gone out of business so we won't get any help there. The door manufacturer may be Kassen and Keller.

My husband has had the door off the track before. I don't believe he has ever taken the roller out. If it would help identify the piece, I am sure he would do it again. Your video was just perfect. I can't wait to show him!