there is no real time scale for a replacement of the filter, or shud i say the pump, cus you have to replace the whole unit
the procedure to change is
1.lift rear seats
2.find metal tank plate and undo all four nuts
3.lift to see the gubbins (technical name
)
4.you'll see about 10 if i recall correctly, small nuts. undo these, but BE CAREFUL, i have already snapped two of the stubs which come out from the tank!
5. disconnect the sender wire and petrol pipes (have rag at hand for spillage)
6. slowly now lift off the metal ring then slowly twist and pull the pump upwards.
7. SWEAR cus of the crappy fiat design of the float which sends the signal to your petrol gauge! if you jiggle a bit, it will come out!
to put it all back in........reverse of getting out
hope this can help mpi people in the future!