Bob,
An easy fix? Forget it. Pull the thing out of the
ground and replace it with hard drawn copper pipe.
'Water drill' it into the ground (keep large hammer handy
for the rocks). Better yet, lay out several hundred
radials (sure easy to tell others to do that, isn't it?).
An 'easy way' and a 'good way' are seldom the same thing.
'Doc

PS - Don't bother pulling the old ground rod out. Just
sink the new one near it.