I've got a pretty bad oil leak in my 1984 300td that is most likely coming from the oil filter housing. When the engine is running and warm I can see oil start to puddle pretty quickly under that section of the engine. When underneath the car the rest of the engine is dry except below and behind the oil filter housing.

I tried tightening the bolts to see if that would make a difference, but they were pretty already tight and the little bit I was able to tighten them didn't stop the leak.

Assuming I need to replace the gasket does anyone have any tips for getting the left most bolt out of the housing? I'm able to get at the other bolts with a 6mm hex ratchet and a stubby hex wrench for the one closest to the steering box, but I can't get anything to work on the left bolt that is behind the lower oil line (I did remove the oil lines and moved them out of the way).

I'm talking about this bolt: