Mercedes fuel pumps

[Mike Morrin]

I was in at a local shop today, and they had a 1990 Merc 560SE (or some
such model) on the hoist, with fuel spewing out of one of the fuel pumps
(everything switched off).

The car has two standard looking Bosch pumps, but they are plumbed in
series, so that the outlet of one pump goes to the inlet of the other.  In
this case the crimped join in the case of the second pump had apparently
burst.

The car had probably sat for a few weeks before the fault happened (stuck
pressure regulator?)

So why put two standard pumps in series?

Is the aluminium body of the pump really rated to take the outlet pressure
of the other pump?

Anyone else seen a failure like this?

regards,
Mike