just so happens i have been having front ballscrew cover problems as well,been setting off the y axis servo to large alarm and binding up when moving to y0 several time over the last few days.
last night at 1 am the ballscrew cover come unglued so to speak and i had to cut a portion off(small end) just to unjam the axis and get the machine to finish operations.
as i am now looking for replacement too any info you come across will be helpful.
thank you
2007 Haas TMP-1 Microscribe MX-5 Mastercam X4 Mill Level 3 Surfaces,Solids Seagate 2 tb hard drive AMD 64x2 8gig ram windows ultimate 7 64bit Geoforce 8800 GTX