I think that the reason you are not getting any responses to your question is that a 1985 420SE is not a US car.

You are also asking for answers that can readily be found online by looking at any of the online vendors - try the "Buy Parts" tab on this site, for instance.

But to comment on your situation. If there are two pump-like things back by the tank, with wiring and fuel line connections, then you have two pumps.

My experience with reviving is that you will need to remove the tank and have it boiled and probably coated. You will need new pumps and a filter. When you remove the main fuel line, there is a strainer that will need to be cleaned. While the tank is out, disconnect the feed and return line at the fuel distributor and blow them out.

With the tank back in and fresh fuel, new filter, and pumps working, connect the feed and fuel lines together at the fuel distributor, jumper the fuel pump relay, and run the pumps for a couple of hours. Then connect the lines to the fuel distributor, and run the pumps for five minutes or so. Then the fuel system should be ready to start the engine. If you take short-cuts, you will almost certainly end up with more problems after the car has run for a while.

You would probably also want to change the oil and filter and spark plugs. With the FP relay and plugs removed, crank the starter until you have oil pressure. Then connect everything up and give it a go.

You may well end up needing injectors, injector seals, a fuel distributor, and a warm-up regulator as well.

Good luck.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe