Can you tell us the diameter of the original pins for the door, as well as the diameter of the caps atop the pins? Is there also any manufacturer label on the door? For more information on bifold doors, see this blog article here.
Thanks for the response. That label that notes this is a "Model C" door makes me think this might be an original Slimfold Bifold door. We carry the newer versions of these pins, and if the critical dimensions match they would work for you. The 21-001 is the bottom corner adjusting pin, and the 21-007 are the other guide pins. Please compare the diameter of the caps and the diameter of the pins, and let me know if they match your old hardware. Also see the other components we've listed on this page. Let me know if you have any other questions.
Greetings, perhaps I can help You and your neighbor have the old Slimfold bi-fold doors. The old plain guide pin in the first photo has been replaced with the 21-007 spring loaded guide pin. The nylon cap for this pin is no longer available, I am afraid. The caps in the second photo look like our upside down 21-105. Slimfold has made it easier with the new pins. You would use one 21-001 bottom threaded adjusting pin. The other three, top pivot pin and two guide pins would be the 21-007. Let me know if you have further inquiries.