Not Alfa but....
I learnt something new today.
I was changing a knocking drop link on the CR-V and, as usual, it was fighting me all the way. I got the top nut to turn 90 degrees but of course the joint just swivelled with it. No problem, just get the angle grinder out. However, I needed to pop out in it so I stuck the wheel back on and...........knocking gone!
I'm guessing the ball wears in one plane only and rotating them puts an unworn part of the ball in contact with the socket? Anyway, new drop link has gone back on the shelf and I'll see how long my ghetto repair lasts. They are the same basic design as Alfa drop links so hopefully may help someone one day.