Join Date: Jul 2011
Location: Cologne, Germany
if I heard a SNAP anywhere on the steering I would be concerned!
Did the tight U turn you made snap off one of the steering end stops (photo, circled in red) maybe? They need to be there, you mustn't 'over steer' these boxes
The S4s have a UJ on the steering shaft under the dash (photo 2) check that for smooth operation and that nothing has entwined itself around it.
other that that, I'd check the steering idler, if that bearing seizes the steering gets harder (though with p/s it is more difficult to feel)
Jack the front of the car and turn the roadwheels by hand and try feel, observe or listen for anything untoward.
Dom - Alfa Spider 1990 S4 - formerly: Alfa 101 Sprint, 2600 Sprint, Montreal - family classics: Jensen Interceptor II, '58 Hooper RR Silver Cloud I, Shadow II, '60 Corvette.