I have expansion joints AKA (Full Expansion Coupling) in my basebaord heating system (Base Ray Cast Iron Baseboards) where the baseboard heaters transition to 3/4" copper in a closet between bedrooms. One of the expansion joints has a little bit of green crud near the fitting and it is leaking small amounts of water. Can I disassembly this fitting and repack it or replace a washer, or do I need to replace the expansion joint? SEE SAMPLE STOCK PHOTOS. If replacement required, are these readily available. I am in southern NJ area.