I’d figure the grease would keep any moisture out.
I see this in Michigan more times than not. I’d guess the salt. I put anti seize on upon reinstallation.
Yep, salt, Everything looks like that where I am near Buffalo. MY son in law just did a rear brake job on his 2013 Silverado. He bought new bolts for the bolt holes on the rotor to force them off and they were not enough to move them, he had to use his torch also. When my 2004 PT Cruiser was 3 years old, I tried to take a look at my rear drum brakes, could not get them off, soaked them in penetrating oil and tried again in a few days and still no go.
I put it back together and figured I would jusy have to destroy the drums when the brakes started making noise. They never did and an idiot talking on his cell phone and turning left while looking right crossed 3 lanes of traffic to total my PT.
That’s an aluminum knuckle, right? Galvanic corrosion probably doesn’t help.
Too bad the area can’t be coated to reduce galv corrosion.
White corrosion on the bearing housing is aluminum oxide… shiny I.D. on the brake caliper hole… It IS an aluminum knuckle.
The cast iron bearing housing is in no way sealed to the knuckle, nor is any anti-seize used but the fit is snug. The iron rusts so and grows in size (iron oxide molecules are bigger than iron molecules) locking it into the knuckle like the knuckle owes it money.