I assume this is for your 300D? Click on "Buy Parts" at the top of this page and it has every put under the sun for these (and other) cars...in fact, here is a direct link to the item page for the washer pump on the fastlane store:

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1UG0IZKG21UY10U99W&year=1982&make=MB&model=300-DT-001&category=P&part=Washer+Pump

You'll notice it says "use with grommet so and so" that is available in the store too, it seals the port the pump fits into against the tank.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)