I often park my car up for more than a month at a time (outside), and the discs always go rusty and horrible. I think the pad even ends up rusting to the disc.

Is there a good way to stop this from happening, as i have to get my k sports skimmed now due to high spots from pad deposits. If i look on the disc, there is still a pad shaped witness mark on the disc, and thats after doing about 100 laps around brands hatch.

 

The best thing would be to push the pads back into the calipers. Even if you used a corrosion inhibitor you would still need to do this. Corrosion inhibitors are not meant for use on brakes so you would need to wipe off before driving.

The slight rust on the swept areas is no issue though as it comes off as soon as you use the brakes - so no need for corrosion inhibitor.

 

You'll not stop it, steel is very reactive and reacts with water, especially slightly acidic water which is rainwater, VERY quickly.
remember that the pads are scraping the discs clean, so you have in effect, new steel. I can WASH mine and there will be rust spots on the diswcs when it dries, it's THAT fast.

 

and the higher quality the disc the more they will rust, just check out the higher cast iron content race type discs on competition cars or the likes of high spec Ducati bikes..........

alyn