Does it resemble this:
http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1U40N9POF1UC12AAU5&year=1980&make=MB&model=280-SE-003&category=E&part=Fuel+Filter&appChassis=_any
If so, do as Ferdman suggested and use wrenches. You'll have 2 connections to loosen, an inlet and an outlet. You'll use 2 wrenches at each one. A wrench to loosen and one to counter. Again, if it's like the one at the URL I listed, it will fit inside a sleeze that's loosened by backing off screw tension. After that's done and the 2 connections are off, it slides out.
As a safety precaution, I pull the ground strap on the battery first because in my case, the pump is nearby. I also lay an old blanket on the ground first. Metal tools dragging across a concrete surface could create spark.
Have a pan handy to catch fuel runoff when filter connections are removed.