Re: knocking from front link bar and antiroll bar
My 156 was knocking badly at the front. I suspected the ARB but found it extremely difficult to isolate the sound and be certain that it was ARB and not the front wishbones. Eventually I removed the 2 drop links, tied the loose end of the ARB with wire and went for a drive. Knocking stopped completely so this confirmed that it was indeed the ARB.
Main dealer quoted me £480 to do this repair. ARB was £47 + 2 drop links at £12 each. So at a £410 saving, I did the job myself. The ARB is sandwiched between the subframe and the body so the subframe needs dropping by 6 inches before the ARB can be removed from one side. So there is a bit to unbolt: power steering rack, exhaust and rear engine mount. I then replaced 4 of the subframe bolts with threaded studs and lowered the subframe down these on nuts withoutr actually fully undoing them. This made it easy to refit / re-align the subframe. Total job took me 3 hours and would have been quicker if it wasn't the first time for me at this job and I was a bit unsure of myself.