Greetings, Wilson,
Amazingly enough, the parts for this regulator setup are most likely still available. Current regulators pretty much have the same ‘guts’ as many vintage models. Check with some of the other SB members as quite a few have spare parts and rebuild kits that they say they can contact you about. As for overhauling yours, take it slowly and be sure to soak parts in a white vinegar/water solution to remove any oxidation. Prepare to scrub if needed. Rinse thoroughly in clean water and dry thoroughly before assembly. If you can access, VDH archives are helpful. I know of a handful of SCUBA service technicians who will work on these and they have the parts you need as manufacturers DON’T sell to folks that don’t have their certifications. Your local Dive Shop will most likely NOT service your rig and tell you they are outdated and dangerous. …take that with a grain of salt. That is why I recommend this handful of shops and technicians who have backstock parts and can cross-reference current parts that are made for your regulator. Go on Facebook and look up The Scuba Museum under ‘Products’. Another source is Tarpoon Dive Center in Hialeah, FL. Ask for Stephanie after 10am W, F, & Sat. There are others such as r. singler.
For help and advice, contact ‘Green Frog’ on SB. He works on Conshelf XIVs as well as others you see in the vintage diving forum on SB. I can’t recall all of their ‘handles’ but they are happy to assist you in any way they can. …why I like SB a lot…if you want to DM me, I will do what I can. You may need to post a few times on SB before you can do this though. I had to do this when I first started.
Scott G. Bonser