So I'm moving the driver's seat forward and I hear a "SNAP" followed by little plastic parts on the carpet. Reaching under, I pull out an intact bracket and the parts of the other one. Diagram numbers 5 and 6

Anyone have this happen? If so, what was the fix?

Maybe I need to lose weight?

 

Those plastic trim pieces cover the seat track edges to make them look more finished. They are all long gone on the C240, and I think 3 of the 8 on the CLK were gone when I sold it.