Lee,
if I understand you correctly, I picture that your loader arms are open on the ends. That is that the bottom (the bucket pivot) and the top (the arm pivot) are both open to the atmosphere. Your problem is that the bottom keeps getting filled with dirt and you are afraid that water entering form the top will be trapped and freeze inside.
If that is the situation then I would suggest that you simply close the openings. weld a plate over the offending cavities and have peace that dirt can no longer intrude where it is not welcome. The top should also be covered so that water does not enter at all. i believe that is what I would do. it seems like a poor idea to leave openings like that in the first place.
Mike