Originally Posted by
Cynikal
Looks like corrosion, maybe from road salt under a spoke?
this was instantly what i thought of.
Originally Posted by
Grand Bois
Galvanic corrosion. Dissimilar metals in contact in the presence of an electrolyte (water).
this is also very likely (and would have been accelerated by above)
it looks
exactly like the corrosion that ate through the aluminum fuel pump control module that was bolted
directly to the steel frame
under my newer truck. (i was not pleased the snowy day it shorted out)