I think that my voltage regulator is the source of my troubles with battery recharging, so I'm trying to buy a replacement. However, the regulator has no part numbers, brand or any mark of any kind on it, so I've been hunting the EPC for the part number. That states that the replacement part number is A 002 154 58 06, which in turn is listed here as having a Hella 5DR 004 241-151 regulator as a possible replacement for the original MB part. However, here, that particular Hella regulator is listed as having a 32mm diameter, while the regulator I took off the vehicle has a 28mm diamater.

So I'm stuck...I don't want to buy the wrong regulator and fry my battery, but I have no idea what the original regulator is. Anyone have any suggestions on how to identify the old regulator? Some pics:







Engine originally (this is in a 1969 L406DG) was an OM615.910...not sure whether it's the original engine, as I can find no engine number on it (couple of places on the engine where it looks like a small plate was riveted to it, as they used to do for engine numbers, I believe), but the identifying plates are long gone. I am of the opinion that it's probably not the original engine, as there's no power steering (which was on the 615.910, according to the EPC), and the oil cap is a different shape (I've been reduced to this kind of identification!), and it's done less than 200,000km, which for a 40 year old engine seems remarkably little.

I can buy a 28mm replacement by Hella, and hope it works...but I don't want to turn the battery into an explosive device...thus hoping that someone here might have some helpful suggestions.

TIA