CTCI Authenticity Chairman
If you own an Early Thunderbird 1955/56/57 sooner or later you will experience oil or Fuel or both leaking from the vent holes in the center body of the pump, photo # 1. If the leak through the vent holes is fuel the lower pump diaphragm is split allowing fuel to seep to the top of the diaphragm and exit through the vent holes.
If the leak through the vent holes is oil the Diaphragm shaft seal, photo # 2 is worn or the seal retainer is dislodged from the housing which allows oil to pass the seal into the vent cavity
Photo # 3. If the seal retainer is dislodged from the housing the oil leak can be more severe because of the large opening it creates into the vent cavity. In all cases the pump must be replaced or disassembled for repair.