The black tank is the reservoir for the PAS (power assisted steering) fluid, could have been over filled. Did you have any probs with the steering, you said you had a few thing sorted out already?
As to the Pulling when Braking sharply, sounds like a sticky brake calliper, ok on slow braking but not reacting fast enough on quick braking.
Looks like another visit to the dealers
you could always look on the bright side, There'll wash your car for you (saves you doing it)