Originally Posted by Diesel911

I am one of them but not the only one.

In post #2 of the below thread see the pic and the green arrow points at the O-ring in the fuel supply/lift pump that separates the fuel from the pump oil sump that intern drains down into the engine sump.

No one has said it has happened so far, but the barrels/elements of MW Fuel Injection pumps are sealed on the bottom with O-rings. However, removing the elements ruins the fuel adjustment that is done for each element. And after those O-rings are replaced, you need to have the pump re-calibrated.

You also need to get the elements back into the hole they came out of and you cannot mix any of the element parts with other elements.

I have not looked for a long time but there is real Bosch and generic made rebuild kits for the fuel supply lift pumps. You need to be sure the kit has the 5mm O-ring because there is a valve replacement kit with zero O-ring in it.

OM617 N/A Lift pump rebuild

There is old threads on the lift pump rebuild with part numbers for the kits.