This sounds to me like the oiling system is being used a bit over-enthusiastically. I disconnected my oiling system many years ago, only ever put grease in the lower nipple (about every 1,000 miles), and am always careful to wipe away any excess from around the stub axle when I finish the greasing operation. I have never had any grease on my brake discs. If you are concerned about kingpin wear, do what everyone else does and fit hard chrome kingpins.
