Well, unfortunately, I already ordered a remanufactured pump for $100 and paid a $50 core... so I need to send them my old pump. I guess it's probably just the gaskets in my old pump that have started to fail, but I'm still scared to pull apart a component like that because I don't really have any professional tools (and I'm not really sure what goes into putting it back together if I disassemble it completely). I guess I should bite the bullet and buy some service manuals one of these days.