Help please. I've done this before and don't know why I'm having trouble this time. I am trying to replace the sending unit in my 1965 GTO fuel tank. The tank is out and empty. I have removed the inner lock ring. I've sprayed PB blaster around the sending unit. I've pulled, pushed, hammered (lightly), twisted. It will not come out. What am I missing? I don't remember this being so difficult before. This is the original unit I believe. Did they glue them in at the factory in 65? Help please?