Close 3D object for printing

I need to print a wheel-to-gear adapter. I modified an existing 3D model to fit a larger gear / bolt pattern, by moving 3 bolt recesses. My CAD-fu is a little bit rusty. I was able to move the primitives which comprise the recesses to the correct locations. I had to explode a few of the faces to move the parts and now I am unable to recreate them to form a close surface. Also a few of the unexploded faces overlap the recesses or have holes from the modification. Attached is the modified model in STEP and FreeCAD format. Attached is the same in DWG format produced using a converter, so the file may be faulty. It might be easier for you to either grab the exploded surfaces from the original or even redo my modification completely. The original is attached and named Wheel_Insert_Inside.stp. The milestones are 1/2 when you get the model done and 1/2 after the model has been successfully printed. The model must ready to print by Tuesday 12.00 UTC.