Aircraft Spruce is a good source of hardware. Check them out at www.aircraftspruce.com. I believe they also sell a fixture that will let you drill your own holes in a nut or bolt head.
At my carrier, we had this same problem. We implemented a policy that drove Mx to always change nose wheels as a set. The other big thing to watch for is that the mechanics are servicing the NLG strut properly, and not just adding more nitrogen every time it gets low.
Does anyone know of anyone who has certified a cryogenic treatment method for aircraft (preferably transport category)brakes? I have heard good things about the effectiveness of this treatment on automotive brakes.