I have a 1951 8n that has a leaking hydraulic system and was curious if I needed a total repair kit with the chambers or the basic kit without the chambers. I am planning on changing the piston to a NAA with a O"ring is this a good move or not. Reason for rebuild is the pump is starting to knock after a good work out and she leaks down even with nothing attached. Was also curious if I needed to purchase one of Zane"s jigs so that I can put everything back to together. If I left something out that I might need out for the rebuild please some one let me know. this is my first rebuild and I work the tractor daily. I really appreciate the help you all gave me on my last post