I do have a service manual if needed I can scan them and send them to you or you can buy a manual yoursef for under 50.00Have a squiz at:
http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=13406
Down the bottom you should see a bit of detail of what to expect inside your pump. Yours will be a different style but the internals should be pretty close.
If you have a poke around, remember to keep it clean clean clean, clean your parts with kero and blow them down with compressed air, don't use rags as you will get fibers stuck in places it shouldn't be.