Suitable replacement parts

We have a home built in the '70's. Almost all of the closets have 89" metal, bifold doors. The doors vary in width depending on the closet opening, but all are the same design. Since it would be a messy and costly hassle to reconfigure the closets and the openings to change to a "modern" door design, I would like to refurbish the existing doors.

I am enclosing pictures but my main concern is the top set of door pins. The top pivot pin is spring loaded. The pin on the other side is not spring loaded, but is set screw adjusted (therefore "fixed"). We have always had trouble keeping those in the track as you open the door. Shouldn't that pin also be spring loaded?

I can clean up the existing spring loaded pivot pins, but would be open to replacing them if you have a suitable replacement part. Obviously, I need to replace all other top pins (spring loaded or not). Do you have any recommendations?

Thanks,

Tony

The diameter of the pins appears to be 1/4". The top of the cap is 3/8" and the flare of the cap measures between 7/16" and 15/32".