Rethink your problem, given where the leak is. These cars are very hard to start if air can get into the fuel lines. If fuel can get out of the fuel filter, I'm guessing air can get in. Resolve that problem first. Tighten up the fuel filter by tightening the large nut on the top of it. If you replace the canister fuel filter, make sure you fill it up with some kind of fuel before replacing it. Diesel purge or ATF or diesel fuel will work. If you replace that filter, also replace the primary filter in the line below.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13