Richard: Thanks again. So I see it is the brake's rotor "splash shield" and have read some more about this being a common problem because the shield being purposefully a bit "flimsy" metal can get bent and/or loose. It also looks like just a single bolt secures it onto an otherwise snug fit on the rear side of the brake and rotor assembly. I will try to jack it up and remove the front wheel and see if I can bend it back into shape (if it's bent) or simply tighten / replace the bolt. I have read this is because someone inexperienced with the Benz may have bent or loosened it during a tire change. This one has brand new tires; I suspect it was a hastily done cheap job by the prior seller. In any event, I am thinking about putting different tires on it for the Spring / Summer, so may be I will just have a proper facility fix it if it remains a problem when they do that. Thanks, again.

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CJTucker