OM617 IP, oil leak from fuel pump gasket
 

I removed the fuel pump from the IP 3 months ago, to fit the new primer pump. Since then, I have had a continuous oil leak from the gasket between the fuel pump and IP body.
One drop of engine oil leaks from the joint every 10 seconds while the engine is running, regardless of what I do:

I replaced the gasket - oil leak continued.
I replaced the gasket and used silicon gasket material - oil leak continued.
I made a cork gasket - oil leak continued.
I made another cork gasket and used silicone gasket material - oil leak continued.

What am I doing wrong?
How can I fix the leak? Is an "O" ring the answer?
SWMBO's car is the offender and I am under pressure to stem the flow of oil onto the driveway.

HELP ME PLEASE.
ps, I did search, but despite quotes, the search engine does not search for phrases, just multiple words [grrr]

Why did you have to remove the whole fuel pump just to replace the primer pump?

How tight are you tightening the bolts? factory spec?

I had a small crack in the body of the pump on my 300D, allowing air into the system. Is it possible you cracked the pump body when you reinstalled it?

Other thoughts
 

This link may help.

Oil Leak location??
http://www.peachparts.com/shopforum/diesel-discussion/39507-oil-leak-location.html#post225076

Thanks for the suggestions.
On the '84 300D is this IP.
http://i34.photobucket.com/albums/d1...z/DSC01252.jpg
As you can see, there is a side cover, behind the fuel pump (removed to repair the oil leak).
There is a neoprene gasket to seal this cover.
Unfortunately, when this was fitted, one of the set screws must have caused the gasket to twist slightly, allowing the gasket seal to be tenuous at best. The neoprene has moved from the part which provided the tenuous seal, resulting in the leak. This allowed one drop every 5 - 10 seconds while the engine was running.
I have used silicone gasket maker to seal the side cover and for once SWMBO's car is not marking all of the spots on her journeys.

It was getting so bad, that the EPA were following the trail of oil spots down the highway ;)
It wouldn't have been long and the car would've joined the dots for them ;)