I’m rebuilding the SLS on my new to me ‘85 TD. The system never worked in the 10 years the PO had it.

I bought a rebuilt pump from a reputable company, new high pressure line, rebuilt the valve with the genuine MB kit, and a new return line.

I filled up the reservoir, crossed my fingers and started the car. At first the reservoir appeared to be going down in fluid and then seem to stop. Then I noticed a leak in the front. The leak appears to be at the head, not where the pump halves fasten together. I check the bolts on the pump and tighten them a bit more. Spec is only 11nm. Yes, I used the supplied gasket. Started it again and the leaking was a lot less but still leaking. I thought maybe I put a little plastic things in the high-pressure line and backward and that was inhibiting the flow. I was going to check that this morning.

I loosened up the bleeder valve and new fluid came out. I’m not sure how long i need to run the engine to completely fill a dry system or do I need to put weight in the rear to help it come to pressure.

I can’t figure out why this rebuilt unit would leak at the pump unless it’s defective. This is my first encounter with SLS so I’m still trying to figure it out. Thanks

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1985 300CD, CA
172 Anthrazitgrau/Palomino 154

1985 300TD, CA
040 Schwarz/Palomino 154/3rd row seat

1985 300TD, CA
473 Champagner/Palomino 154/Cargo cover