is this a Mondeo ? certain fords are a nightmare unless you know the trick !! Garages (including main dealers ) use a brake bleeder or similiar to suck the diesel through, its the only way. I have seen a qualified mechanic spend hours trying until someone pointed him in the right direction.
Ford main dealers get vehicles recovered in on a regular basis to get them back on the road after what should have been a 5min job changing a fuel filter on a sunday afternoon,doh!