Ball screw/nut repair

I was able to get my Yamazen mill up and running and check the
backlash. Both the Z and X are less than 0.001. The Y is 0.008. I
checked the Y ball screw and I can feel a "crunching" when I rotate it
back and for. It looks like I need to get it overhauled. Does anyone
know of a place (Northern California would be prefered) that I can get
a ballscrew overhauled?

Thanks

Vince