On my 240D manual I also tried the bottom half of the rear oil seal trick when I had my engine out last winter for a broken timing chain repair. It didn't leak a lot before, but it doesn't leak at all now. Changing the clutch is much easier with the engine out, but it took me a day to pull it, and a day+ to reinstall. Bleeding the clutch was the biggest pain outside gettting the Injection Pump timing correct.

Still, I believe if I pulled the engine just to replace the seal, I'd drop the crank and do the whole thing.

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1976 240D
1987 560SL
2007 E320 Bluetec
1998 C280 (now son’s car)
1982 240D Manual - Sold