Had the same type issue a year ago. The solution was to buy repair nipple from MB. Pretty cheap maybe $6. Do a search on this site for the PN. Also bought the correct drill and metric tap from MSD. You cut off the old nipple flush. Drill the hole and tap it. The repair nipple threads in. Of course you need to clean it out very well after the repair. Total cost was approx $70 and I have the drill & tap for future work.

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81 300D Turbo 190K sold
83 300sd 319K best $500 I ever spent-daily driverw/ 2 tank WVO set up