I was looking at a pic of an IP and evidently there is a threaded steel insert cast in to the Fuel Injection Pumps where the Banjo Bolts screw into. I think it is possible that the Steel Insert could have become loose in the Fuel Injection Pump Housing.

Inspect the Banjo Bolt closely for cracks between the holes.

If it was me I would degrease the whole area with Brake Cleaner and get out an Magnifying Glass and a Light if needed and have someone start the Engine and pin point exactly where the leak is coming from.

On person has had the O-ring between the Element and the Fuel Injection Pump Housing leak. That means the leak would be under the 13mm Nuts (don't remove the 13mm Nuts without instructions on marking the Element position).

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84 300D, 82 Volvo 244Gl Diesel