7.5mm inner diameter for the fuel hose. Get about 2 feet. Under the driver side at the fuel tank you will find a vent and return line. these use about 6 inches each.
On the pasenger side of the rear you will find the screen and fuel line that goes into the screen The screen uses a 46 MM wrench to get it out. Buy the fuel line that goes into the screen. Take out all the fuel by disconnecting the screen hose and allowing the tank to drain. Clean the screen. If it is broken, replace it. Use brake cleaning fluid to clean it.
In the engine compartment replace the rubbe hose that is attached to the inline filter. Replace your inline and main filter.
Get a new "cigar hose". The injector pump does need it to absorb pulsing from the injection pump.

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car