I'm reinstalling the fuel filter housing on the OM615 out of my '76 206D, and came across something I forgot to properly document as I was taking everything apart. I've got three banjo fittings on the housing -- but one bolt is different! Compared to the two others which have multiple large holes, one bolt only has one very small hole:


I currently have it in the line going to the injection pump input -- is this correct? Is this bolt even correct, or should all three have the same large holes?