Disc caliper overhaul kits?

Hello, i want to put a kit through my single piston calipers. All i can see on the internet is exchange calipers (remanufactered -need to give them your old ones or "core"). Being in Australia it is hard to find things like this for US vehicles. And sending heavy parcels to the US is very expensive. Does anyone know of parts or brakes places anywhere in the USA where i can buy the overhaul kit? So i can so it myself.

Thanks!