Sliding glass door wheels

Hello and thank you for your help. This is a very old sliding glass door wheel in Canada. It is a very simple aluminum frame holding a single wheel. It is not square. I believe it is called a parallelogram with one adjustment screw at the top. There is a slot below the top rail to hold a nut that engages the screw after it's installed in the frame. I am sorry that I didn't take more pictures but if more pictures will help please let me know and I will certainly take more and forward them to you. Any help you could give me would be great. Thank you so much. My name is Prem.