PeachParts Mercedes-Benz Forum - Parts number explanation

Here's an excerpt from a detailed description of the Mercedes part number system...

Quote:

Originally Posted by http://www.rockymountainmoggers.com/mbpartnumbersystem.html

Example part number: A 427 421 20 98

This can be broken down as follows: the "A" indicates it is a regular Mercedes-Benz part. The 427 is the model this part was first used on and also indicates it is a proprietary part. The "421" indicates it is part of the brake system, and further more is a hydraulic component rather than pneumatic which would use a "43x" in this position. "20" indicates this is the twentieth version of this part, the "98" is the "part number" in the master listing. The ninety eighth part.

So, in your case, comparing part numbers 124 830 18 85 and 124 830 30 85, they appear to be the same part, and just different versions. While this doesn't guarantee they are the same, it indicates that they probably aren't wildly different.

I have no experience with the exact parts you are looking at, but in my (limited) experience with other parts, I've never had a compatibility issue when swapping parts where only the version differed. Often when I get new parts from the mercedes dealership, the new parts have a higher version than the original part I am replacing (and they have always been compatible).

Edit: According to the EPC, the 18 part was used in the 124.193 (300D) and 124.133 (300DT). The 30 part was used in the 124.050 (300CE), 124.026 (300E-2.6), 124.030 (300E) and 124.090 (300TE). The parts may be similar, but the EPC doesn't explicitly show the 30 part as being a direct replacement for the 18.