what is the issue with the WP impeller contacting the case?  when i
replaced my water pump last fall (with a hepu from volkscafe), i
noticed that this had occured from the failed bearing in the old pump.
 there was a small, arc shaped divot of maybe 1mm depth "machined"
into the case behind the water pump.  it was not in any area that the
new pump had to seal to, so i did not think it would be a problem.  i
was a little concerned about the presence of metal shavings in my
cooling system so i backflushed it quite thoroughly.

is there some problem that i did not think of in just putting a new
pump on?  what possible issues can arise from not repairing the damage
done by my old pump?  and what does the repair entail?  (the rescue
squad link above didn't work...).

Ben.