ToiletPro.com and Akitchengallery.co are some of the websites that feature Kohler parts diagrams as of 2015. These diagrams show the parts that make up various components of the Kohler plumbing units and a description of each part.
ToiletPro.com offers parts diagrams for the Kohler 4520 toilet model. Both diagrams are for the two-piece model, and the second shows replacement parts for the toilet, along with the codes to use for placing an order for a replacement.
Akitchengallery.com shows diagrams of Kohler kitchen faucet parts, each with a name and a corresponding part number. Dashed lines show the places for fixing each part.