One rear brake on our Mini was not functioning well so we took a look at it. The rubber boot protecting the guide pin was distorted so we took it out. Here's what we found. Lots of white build up. It came out with a file and wire brush but I'd like to prevent this in the future. Will Anti-seize compound work or do I need something else? I'm in the northeast, lots of snow and salt in the winter. Thanks

 

The rears unfortunately tend to fail, corrosion or not...
Externally you can paint them....
Internally....more flushing....
But short pulling off the rubber bushings on them to lube them (yes, if you look at the mini inspection 1+2 list, it does say lube and inspect....
Magnesium-chloride is even worse than salt corrosion wise....you can try to rinse stuff off more, but most of the typically oily anti-corrosion sprays are not going to play well with brake parts....
And living in the NE, I had my rear OEM brake rotors fail inspection...barely 4 years.....the edges were corroding and puffing... coming off in layers...the caliper survived till it was about 10 years old.