Hi, and welcome to the best Mercedes forum on the web... !
As you note, there is much expertise here and open sharing of knowledge is common.
Unfortunately, I don't know anything about the W210, but many here do...
It might be helpful if you were to take a digital photo of what you're attempting to describe and I'm sure someone can indentify it for you.
Congrats on your doing some of your own maintenance... ! A rewarding experience that will save you a bunch of money.
KenP