Zinc Foil 41331885099

[528i-1981]

What is the purpose of these small squares of zinc when mounting the apron? This same part is used in completely different locations on the E28 and E36.

[Champie12]

Thats interesting, I'm not sure exactly but I feel like it would have to do with corrosion prevention (so you can get your nuts off and the sheet metal wont rust)? Or perhaps it spreads the load the clamping force the nut and bolt are exerting on the body's sheet metal?

[528i-1981]

I found a reference to zinc foil on a VW board used for mounting the fender, and it's purpose was as a sacrificial anode for corrosion protection. The consensus there is that they don't provide much protection. There weren't any foil squares on the apron when I removed it, so either the PO had the apron off and didn't replace these or else they were consumed and vanished after 38 years.