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

SLS pump reseal, o-ring sizes?

Which referenced this thread:

SLS Pump Leak (Unusual)

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!

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

Pics. The first is the back interface part that just sits in place. In this pic I have replaced the o-rings with originals. As you can see there is a slight gap when I push it forward. This is good. With the new o-rings I sourced there was no gap and the back got scored. Metal shavings made it into the oil system.

The second pic shows the gap between the body and face. This is a normal gap and this one is okay. With the replacement o-rings the gap was MUCH larger.

Attached Thumbnails

   

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

An easier way than hunting around for the rings that may or may not fit is to contact

George Murphy
Performance Analysis Company

865-482-9175

I got a rebuild kit for the SLS pump on my 190. I think it was about $40-$50 or so. Had the 4 O-rings, paper seal for the back side as well as the cam seal for the back side. Also gave instructions for repair.

The rings fit perfect and I had no issues.

__________________
Sent from an agnostic abacus

2014 C250 21,XXX my new DD ** 2013 GLK 350 18,000 Wife's new DD**

- With out god, life is everything.
- God is an ever receding pocket of scientific ignorance that's getting smaller and smaller as time moves on..." Neil DeGrasse Tyson
- You can pray for me, I'll think for you.
- When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours.

Thats expensive considering what one gets. 30 o-rings cost me $24.00!! Thats 10 kits. Then again, they did not work! lol And a new pump is over $1,200.00!

If my leak continues, I will check it out. But its seems to have slowed A LOT. But I like the idea of a new cam seal. Mine looked good, but failure would be bad.

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

It's may be $25 more than you spent and it would have worked the first time. How much is your time worth?

Mine was leaking at the cam seal. If you do replace it make sure you put it in deep enough. I sunk mine to where it was just below the rim of the pump housing. I had it flush at first but it leaked like a sieve. Took it off and sunk it in a tiny bit more and all was good in the hood.

__________________
Sent from an agnostic abacus

2014 C250 21,XXX my new DD ** 2013 GLK 350 18,000 Wife's new DD**

- With out god, life is everything.
- God is an ever receding pocket of scientific ignorance that's getting smaller and smaller as time moves on..." Neil DeGrasse Tyson
- You can pray for me, I'll think for you.
- When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours.

I've replaced all the O-rings but it leaks. @davidmash: how did you know your seal was leaking? Was it dripping down the front of the engine? If so, it's hard for me to understand how seating the rear shaft seal deeper stopped the leaking that must get past the cover o-ring.
Mine is leaking badly between the halves when under pressure, but if anything I'd think that means the rear seal is too deep (but it's flush).
UPDATE: I figured out the 2 o-rings I put on the center piece were too small (I ordered the wrong OD and had to stretch them an inch to put them on). I measured the originals and got 2mm cs x 62mm ID, which agrees with what someone else posted for a later car w/ same pump (mine is an '85 300TD).
The cover O-ring btw seems to be 2mm x 61mm. I think you can get that one from the dealer but someone complained about the quality (and I think it's one of those superceded part numbers, not necessarily the same as the original part).