Datsun Roadster Diaphragm for Kyosan original fuel pump only.
Datsun Roadster Fuel Pump Diaphragm NISSAN
Fuel pump diaphragm for most 311 model roadster with the original Kyosan Denki fuel pumps. The pictured part is the internal working diaphragm that usually leaks or fails in the pump.
Check to make sure your pump is re-buildable. Pumps with the ball type round peg end are subject and often not re-buildable. Your diaphragm should match the one in this picture and have a T handle style peg at the top.