Those pesky fuel pumps .......

[SNBmerc]

So does anyone know just what it is about those Bosch fuel pumps that makes them stop running or run intermittently?

I've found that whacking them with the ignition on gets 'em spinning. And my old Golf / Rabbit GTi had one fail (almost identical to those used on the Mercedes), but the brass bushing / bearing at the end opposite the pump was so badly worn the armature would jam against the stator magnets. Easy to see why that would stop it, but the Mercedes' I have now doesn't seem to suffer the same wear problem.

Just curious .......

Any ideas?

Simon.