My car's been knocking from the front drivers side since before Christmas. Passed the MOT like this however, but it's annoying so I had a look at it yesterday. I'd checked the drop link before the MOT to see if that was causing the knocking and it "appeared" OK. So I was expecting it to be the ARB bush on the drivers side. I was going to try the urethane sealant trick to kill the noise. However, the bush "looked" OK, I couldn't see any splits, cracks, nowhere where you could actually inject sealant. So I took off the drop link on the drivers side and went for a drive. The knocking had gone, so definitely ARB related. I also tried waggling the end of the ARB, which should have been unloaded with the drop link removed, and couldn't feel any looseness or hear any knocking from the ARB bush.
With the drop link removed I noticed this time that one end was much easier to move compared to the other end (which required real effort to move). However there was no movement in the slacker end that would obviously cause it to knock, i.e. the ball didn't rattle around in the socket. I pulled the rubber boot off and there was some orange rust staining on the ball so I'm going to replace the drop link anyway (Not a lot of grease in there !, Birth brand, hmmm). So, to cut a long story short, does any lack of tightness in drop link joints mean knocking when fully loaded on the car ? And can an ARB bush look OK but still knock ?