I haven't personally replaced Benz liners but I was led to believe that they were wet like big US Diesel liners. With the big Diesel liners you simply pull the old ones and install the new ones with no further machining. I had the impression that this was the case with the OM617. Evidently that is not the case - I sit corrected (I'm sitting at the computer so I don't "stand" corrected!).

The way this works is that there is a step machined at the top of the bore and the liner has a lip that sits into that step. At the bottom of the bore there's an O-ring that seals the liner to the block. When you assemble it everything lines up and you're done. The head holds the liner from climbing up and the step stops it from sliding down. Some of these rebuild kits come with pistons and rings and some do not. There are even kits with gaskets and a rebuilt head so at the end you have a whole fresh engine. Not cheap but nothing is for the big fellas.

Dan