Repairing a Single Circuit Ballnut

 
Start with a clean tray and surface on which to work.
 
Remove the screws holding the ballnut return tube.
 
Remove the ballnut return tube.
 
Add a few drops of any kerosene based lubricant to the balls.  WD40 or Liquid Wrench works well.  Add enough to wash down the balls.
 
Place the empty ballnut on the ballscrew.
 
Wiggle the ballnut around until a channel is formed at the recirculation tube.  Use a magnetic point (a magnetized nail will work) to drop the balls one at a time.

  Make sure none of the balls try to go the wrong direction and fall out of the back of the nut.
 
Using a non-magnetic blunt point, press the balls down every now and then.  Another thing is to gently turn the ballscrew so the balls circulate inward.
 
As you get near the end you will need to push in the balls from the other side.  This gets out any extra space between the balls.
 
The ballnut is now full of balls.  No more balls can be stuffed in with out balls falling out of the sides.
 
Pack the ballnut return tube with Vaseline.
 
Place any remaining balls into the Vaseline.
 
Put both halves together and put the tube back on the nut.  Replace the holding strap and the screws.
 
Run the ballnut back and forth a few turns, if any balls fall out, remove the return tube and stuff them in as well.  Then complete the last few steps again with the remaining balls.