More NAC - Rotor mystery

[mike claire]

I appreciate your indulgence gents, because this is 180 degrees away from
turbo/quattro.  The link below points to shots of of the front brakes on my
'98 Grand Caravan.  I bought it fairly recently (took it in trade actually -
he got my '84 300TD and I got $4K plus a well kept Caravan).

I have never been able to get ABS to kick in, just not enough brake power.
Now I know why.  There was only 1 inch of pad contact, and it wasn't close
to the outside of the rotor.
http://picasaweb.google.com/ebaytechextras/Rotors


These brakes passed NH State Inspection 2 weeks ago.  Obviously they
observed the pads from the side and determined there was plenty left on
them.  The basket weave rims makes it tough to see the rotors.

See how much pad material is left?  These brakes were NOT down to the
rivets.

What can possible cause this consistent groove in the center of each pad?

I have replacement parts ready to go on, but I'm looking for input before I
proceed.


Many thanks
Mike