There is no manual that I know of explaining how to replace the bearings on the spindle. You can look at the breakdown to see how to disassemble the quill assembly. After that you will need to press the bearings off of the spindle with a bearing press. Once they are off make sure your spindle has not been scarred or pitted from the bearing if it is replace the spindle also. Replace the bearings and reassemble the spindle and quill assembly. I hope this helps.
WJA