If you email Dave at Hollister he is very helpful, or you can download the instructions and parts list off his website. But I used the OEM 2003 Chevy 2500 HD front rubber lines from Napa, rather than the part numbers Dave had. They are 1/4" and he recommended 3/16". But I needed it on the road and I read a lot of articles that said there is no pressure difference between the 2 sizes. Mine works fine at 1/4" for what its worth.
