This is a modified version of the OhmEye's Z Axis constrainer: http://ohmeye.com/download/mendelmax/ohmeye_mm2_isolator_constraint.stl. I wanted to have a little less slop than his allowed, so I designed a modified version, shown here. You'll want to use this along with OhmEye's Z Axis Isolator: http://ohmeye.com/download/mendelmax/ohmeye_mm2_isolator_release.STL.You'll need a total of four of these parts. Once you've printed them, they should fit into place without having to disassemble any of the printer. You can find more about OhmEye's Z axis isolator here: http://www.ohmeye.com/2013/reprap-mendelmax-2-0-z-axis-isolation/.