Dart Gold Pumping Leaking Help

[thanhjenn]

I acquired a Dart gold pump a while back. Now installing pump, and it is leaking. Water is coming out of the bottom bolt. Does anyone know why and how it can be fixed.
update: changed 0 ring and lub with silicone lub, undone bolt and put back together and still no luck. Finally took apart another dart pump I have and replace body and no leak. what to do with the extra now? inspected plastic body and no cracks.