I have an early 250SL, and the grease fittings work just fine. However, my car was restored in 2000 and the fittings may have been replaced, but if so they were still the proper metric style. I have a small hand held grease gun that has not caused any issues. I will also add that I have the car up on a lift, so I can access the zerks quite easily from below with have to crawl on the concrete.