Knocking noise from rear Alfa 156
My Alfa 156 is making a knocking noise, sounds like its coming from the rear. It does it on uneven surfaces, when on smooth surface its fine. The noise to our recollection only started after the car had had its fuel pump (located in the petrol tank) replaced. I've had a look through the forums has this has been reported a few times, i've had the car up on stands and had a look underneath and cant spot anything obvious, i tried the trick of applying hand brake very slightly when the noise starts to see if its the brake pads knocking but this didnt stop the noise.
My car is a 2005 156 2.0 JTS Veloce, with 40,000 miles on the clock.
Any suggestions as to what the problem could be ?