the engine bay is very cramped on the 4-pot mondy's, never mind the v6 ones!

there is a long snakey pipe goes from the pas tank to the pump which is known to fray and leak, but it isnt a very common prob.

more likely PAS leaks on the mondeo's are usually due to a dodgy steering rack, or the pas cooler (behind the bumper) rusts and leaks. if it is the latter, it is very easy to fix (and they cost approx £60 for a new one from ford), if yours needs a new steering rack the sub-frame has to be dropped and it is a very big job.

a recon rack is about £120, but i had one fitted on mine and it started leaking within 6 months. a new genuine ford rack is about £350-400 i think.