The fellow who sells these rebuild kits and rebuilt pumps on ebay is a hardcore Cummins man and has hundreds of thousands of miles of experience driving Dodge CTD duallies across the country. Because of his vast experience with the CTD in the Ram he decided to offer other Cummins fans more economical ways to solve the common problems such as the vacuum pump rebuild kit . As far as I know, he's the only source for this vacuum rebuild kit (he originally developed it). From time to time he offers rebuilt NV4500s and NV5600s at reasonable prices which you will see on ebay or his website. I've lost track of his website, perhaps someone else has it and will post it.