If it turns out that the leak is coming from the union that is screwed into the fuel pump - rather than the pipe onto the union - have a look here. There may be some pictures that help you (although it isn't the pump on your car as far as I know).

Refreshing the fuel pump on an OM617 (European spec – non turbo)

The rubber O rings under the union have an outside diameter of 22mm on this pump.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!