I have several Slimfold Model "E" bifold doors that need replacement parts. The specific parts are the pivot pins and plastic caps. The doors should be from around 1985. The pins are 3/16" diameter on the end cap end, 1/4" pin diameter, and 6 3/8" long. What part numbers do I need for replacement? The pins, sleeves, and springs are in good condition. Can I just replace the end caps? If so, is it just a simple matter of removing the old end caps and snapping the new ones on the existing pins? Thanks