The central locking Seat 2000

Hi

The central locking on my SEAT (which uses the same system to Polos and Golfs of that age) has developed a leak. When one locks the doors, they all still lock, but the vacuum pump continues to run for about half a minute, after which point the doors will not unlock automatically. It was more of an inconvenience when I couldn't easily open the fuel filler cap despite following the instructions in the manual!

I have found the source of the leak to be the locking mechanism for the fuel filler cap; fiddling with the mechanism gets the locking working normally. Unfortunately the mechanism is quite inaccessible as it's between the two metal panels; I have tried putting grease around the metal pin that moves, but this hasn't resolved the issue.

If someone kan help me and give me any advice

Sinserlly