check valve

[Jeff Mruss <rmruss@pangea.ca>]

Hope someone can help me with this, checked the archives, but couldn't find the info I need.

Can anyone tell me what the check valves on a PS pump do?  I rebuilt my pump last fall, but didn't touch the check valves and the rebuild was unsuccesful.  I ended up getting a used pump which I'm not satisfied with as it tends to leak down when the car is parked.  

I decided to see if I could remove the check valves on my old pump to take a look at them.  I didn't think I'd get them out since someone (Phil I think) had broken an allen socket trying to get them off.  The check valves came out really easily, and I'm wondering if the fact that they were not properly tightened could have been the reason my rebuild attempt failed.  Any thoughts, comments?  Oh, car is an '84 5KS.

Thanks,

Jeff Mruss