Replacement Threshold and track/seals
I would love to replace the threshold and as much of the seals/hardware as possible, and then was planning to prep and repaint the doors themselves again. Any help in identifying the parts still available would be great. I suspect the door is original to the home, so probably early to mid 90's.
Thanks for posting. I am afraid we do not replace thresholds, and so we won't be able to help with that particular part; apologies for the inconvenience. However, if the door is operating roughly, the culprit is likely either the sliding glass door track (the portion of the threshold with the raised rail), and the rollers in the door that move along that track. You'll want to inspect these components first, which this guide here gives some tips for. If the track is damaged, you may be able to replace it with our 80-106. Watch the video below which explains how to do this.
If the rollers are damaged, see the videos below which explain how to remove and replace them, and also the information we'll need from you to identify a replacement. Let me know if you have further inquiries.