Rear Bumber Corrosion

[keynsham1]

I have just removed the lower valence from my rear bumper (Apologies for English terminology!) and found the bumper has massive amounts of corrosion where the screws are. I suppose putting steel screws directly in Aluminium (Oops, English spelling again!) is asking for trouble. Has anyone seen this before, and is it reparable?

[ganun]

I've seen the aluminum turn to what looks like pastry.
Delaminated in layers, attacking it with a grinder reveals
It is not limited to the surface.
Find a replacement.

[Jerome74911S]

I'm not an expert on this, but my understanding is that ferrous and non-ferrous metals, when bolted together like this will always corrode, especially in a corrosive atmosphere. The aluminium bodies of old Cobras that were in contact with steel fasteners and frames corroded in this manner, as did/do other cars with similar configurations.

It may be simpler for you to cut out the bad parts and weld in new aluminium, rather than find a good replacement piece in the UK.