Well, several hours later and I do not know if I fixed the leak. Concerning this thread:

http://www.peachparts.com/shopforum/tech-help/310209-sls-pump-reseal-o-ring-sizes.html

Which referenced this thread:

http://www.peachparts.com/shopforum/diesel-discussion/306343-sls-pump-leak-unusual.html

The o-ring sizes were NOT the ones for my pump. There are three. With my pump I found an o-ring had cracked from age/abuse (fluid & heat). Fortunately that is the one o-ring I was able to use.

There is an o-ring in the main body on the inside bottom. Very hard to see. The thicker o-ring goes there since a thin one is too thin of the same diameter. However, its too thick. This causes the insert to sit just a little too high and the screws do not compress it enough, apparently.

Then there is a smaller diameter one for the top of the insert. This seals the face. Odd location since one would think there would be another on the far outside where the to halves meet. But there is none. The o-ring I got has the same issue, just a little too thick.

The last o-ring, which I did replace and was cracked, goes around the outside of the insert at its top edge. The one I got was a little too large, but worked. I had to use a soft object and push the o-ring around the edge to get the insert to drop in.

The problem is that the thicker o-rings are thick enough to prevent proper compression of the whole unit. This lets the came float forward and back far too much. Normally it does float, but with the face too far out it rides so far in that the interface part (metal "coin" with an X cut inside) rides on the surface of the back!!!

When I fired up the car after being happy things went well and not spilling any fluid I heard some bad sounds. The sound may have been the lack of viscus fan. I did not know the pulley was also secured by the screws. Duh! However, the sound of fluid pouring onto the floor told me something was not right!!!

Sure enough, SLS fluid all over. The leak was a LITTLE worse than before.

Took it all apart again. Since I could not run the pump dry, I got fluid all over. Tip: I use the return line to the tank and a hose to empty fluid into a canister. This empties the tank and pump. Just dont let it go too long or you will get a lot of air in the system

I found the scoring on the back side of the pump and it was clear there was an issue. I even thought upon first assembly the gap between the face an body was a little too big. Although I am not sure where the fluid came from. The scoring on the back I understand, but the o-rings stayed in place. And in theory even the large o-rings should have sealed even if the cam floated too far.

Anyway, I have some pics but I am not in the mood to upload right now. I think we need to find the exact size of o-rings needed. Not that I can do this project again. I got it right in the end but cross-threaded the high pressure line something bad upon second install. Overall this was NOT a fun project. Even the viscus fan bolts put up a fight. I had to drill one out. I think I would rather do the ball joints again!

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1991 560 SEL / 185k miles
1992 750il / 17k miles - project car