Leaks in the fuel lid where the aphorad goes

Hi, I have a 90C Peugeot 406 HDI the problem that I have to escape fuel because of the fuel cover where the aforerator goes changed the challenge and cover but it continues to escape what the cause will be.
The mechanic says that it can be due to the fuel sensor that there is a lot of pressure on the fuel return and therefore escapes the lid.
If someone can advise me what the cause may be.

Lose through the Board, as the deformed deposit is. The empty deposit is appropriate and checks the deformation of the thread plane. Turn off a bullshit with a new joint with the disassembled deposit. At the mounted r.