Fuel smell

Hi all, I owe a 1991 cabriolet GTI and wanted to know why if I did a full tank it would smell as if fuel was leaking but if below half full it doesn't. Could it be that the tank needs replacing. Any advice is much appreciated

It could be the seal on top of the fuel tank, if you remove the base of the back seat and the round black cover you should see the top of the fuel tank and the fuel tank sender which has a rubber o ring.
Look to see if you can see and marks on the tank or fill the tank and leave the back seat and cover off to see if fuel leaks but make sure your window is open when driving around and don't go smoking in there,  

Thanks Mark1gls, will try that and see how this goes as it's raining and turning cold this will be probably be looked at when I get a chance, just in case it is the seal is there anywhere I can get hold of it. Is dealers out of the question?

New fuel tank sender seal.

https://www.ebay.co.uk/itm/333713446469?fits=Plat_Gen%3AMK+I%7CModel%3AGolf&hash=item4db2df1645:g:FWAAAOSwB95fVjOC&amdata=enc%3AAQAIAAAA0CubiXSDrkXy0ru9DFId%2FqN84R%2BozK%2F%2BnFTIWqoPiwLB3%2B%2BnBRchWUNKOTIPMoaSixOI3juiljDtxCstDYF5RNAjYpUPelkX%2B98ykMOAtpezfCZbNfKWX%2B4ux8w0TvM2BxRzy4IvJ4ejTGAftlctqxUS1RsSqt4XOF78niMdQuWMFdwybVJT2Bc1WZ7zsDDhHyIvrImdTJl%2B00O8jPS3IsHPr4aKQdmi4ligll9yCIc3MTPMw%2F0cpL3E3%2FRZXTRvjS%2ByuoQIM3koMcxitXeeS9I%3D%7Ctkp%3ABk9SR_7OzIj2Yg

most times if I had a fuel smell in the Car, it was usually the stupid screw clamps that I had on the car.  It is one of those things that you don't look at.  Yes I have had the Sender seal go bad, but most times it was.



These clamps clamp on small diameters elliptical and not circumferential and can leak because of it.
Use either the Spring clamps


or



When replacing the Seal or removing the IN-Tank pump. I have dropped that dang filter off when extracting it from the car, So I had a Eureka moment.  Tie a string around it then after it is inserted and prior to locking it in-place cut the string, and remove it.