99 A6 brake Problem????

["J. Kris Baca" <kris.baca@nwa.com>]

I just bought an A6 and occasionally the brakes feel *very* strange.  It
has happened twice now in 2 weeks.  Both times it was when I was leaving
a parking lot and braking to see if the road was clear.  What happens is
that the brake pedal feels like it is connected directly to the calipers
and I hear and feel a grinding type noise. It's as if the power brakes
completely shut off.  I really have to stand hard on the brakes and the
pedal actually vibrates my leg.  Then once the vehicle stops and I take
my foot off the brake pedal and reapply it, they work normally.  This
has never happened on the highway or anywhere else.  Has this happened
to anyone else?  I can't imagine it's normal.

Thanks!