all i did was wire wool or brush the flaking rust off, some fine grit wet and dry paper, then wipe with white spirit to get rid of the grease etc, then get some hammerite straight on paint, and wack it on, the first coat wont look too pretty, but the second should look better.
also, in red take your time as the brush strokes are very visible, so make sure they all run in the same direction.
and do not drive your car for the rest of the day to make sure the paint dries before your calipers get hot under braking.
hope that helps?