MG Car Repair: Fuel Tank, mg midget, fuel leak

Question
I recently FILLED my 1971 MG Midget with Fuel (Right to the brim. I now seem to have a leak. At half full there was no leak. Have I just overfilled, Is there an overflow that release fuel from tank? Or I suppose i could have a hole in tank at higher point. With half a tank there is no leak?

Answer
Hi Malcolm,
You need to look at the evaporative loss system because they do run vapor lines out of the top of the tank to a separator tank and if the vapor line/s have gotten dryrotted or cracked it could be a fuel leak when the tank is full or even mostly full due to fuel splashing.
The separator tank should be in the trunk on the side.
Howard