Gold plating a previously plated surface may be tricky. Getting good adhesion is the issue. I am wondering why the original gold plate is comming off? Surely, you haven't made thousands of connections? I mention this because the original plate was either extremely thin or defective.
Also, be aware that most gold plating solutions use cyanide based chemistry, or in some cases a corrosive chloride based chemistry.
Also, be aware that most gold plating solutions use cyanide based chemistry, or in some cases a corrosive chloride based chemistry.