Originally Posted by dmorrison

I looked at the EPC diagram of the 124 300Td and it looks like the 123 setup. Phil's picture shows it to be the same setup also. Go under the car and in the center , or so, of the tank should be a large aluminum nut looking thing. this is probably your filter. Drain the tank as much as you can via one of the rubber hoses. Then remove the filter. I'm not sure what size wrench. For the wagon I used a bolt head with 2 nuts jambed on the bolt. Measure the size you need and get the appropriate wrench or bolt. Clean the screen with carb cleaner and if it is algae then treat the tank.
Have a bucket to catch the fuel left in the tank when you pull the screen.
Get a new Oring for the screen from the dealer or Phil if he can get it.

http://catalog.peachparts.com/ShopByVehicle.epc?q=1987-Mb-300td--Turbo--Wagon-Fuel--Delivery&yearid=1987%40%401987&makeid=MB%40%40MB%40%40X&modelid=300%2DTDT%2D002%40%40300TD+Turbo+Wagon&catid=E%40%40Fuel+Delivery&subcatid=E1011@@Fuel+Screen+O%2DRing&mode=PA

Dave