Gas Leak rear on 1990 Mercedes-Benz 560SEL

Gas leak in rear not from tank

Asked by for the 1990 Mercedes-Benz 560SEL
The fuel pumps and filter are located In the right rear by the axle, there are also several fuel line lines in the rear. Does it leak worse when engine is running or vehicle just parked?
When running

The leak is from the fuel pump area and forward to engine, since pressure is higher in those lines with vehicle running. Vehicle must be put on a lift to locate leak.