I have been chasing suspension noises for some time. Even after changing the idler, ball joints, control arm bushings, the noise was back today. As bad as ever.
I jacked car up and had wife turn wheel back and forth while I listened. Squeaking and clicking noise seemed to everywhere. I then tried with stethoscope. I found that it was definitely coming from the top of idler pivot. Hard to see the cause, but likely cup rubbing on top rubber insert.
Then I recalled seeing something in FSM! (Idler arm is of course at top on our 107s)
See note b) !!
I removed the pivot bolt and the lower metal sleeve (5). I compared this Lemfoerder sleeve with the original out of my car (older style without flutes on rubber). I found that the original sleeves were 0.5mm longer! (diameter was also different) Exterior surface showed kind of coarse machining marks. Original is smooth. This is the surface that turns inside the sleeve in the rubber bushing, so questionable. May be OK.
As the FSM suggested, I installed a 0.5mm shim between the metal sleeves. I tried turning the steering wheel and it does seem smoother. But still has the metal on rubber sound. Put in another shim to bring total to 1.3mm. Road tested. Still some rubber noise as well as the clicking I have been trying to chase down.
Removed Lemfoerder kit from car. It looked like the upper metal sleeve had not been turning in the upper metal/rubber insert. No doubt because of discrepancy in length of the metal sleeves. As a result the rubber bushing had been turning in the chassis tube. This would explain the noise.
Next measured the chassis tube and compared with the assembled length of the Lemfoerder kit to try and come up with a shim thickness that will work.
Chassis idler arm tube. - 83mm long +/- depending on where measured.
With upper and lower bolted up tight (using old bolt/nut), measured distance between the surfaces that bear on the chassis tube ( metal plate on inner side of rubber bushings):
Original parts removed from car: 82.5-82.9mm
New Lemfoerder parts: 80.6-80.8mm (~2mm shorter than original)
FSM says that there can be 0.5mm slack. So that would say that the distance between bearing surface could be 83mm to 83.5mm.
This means that Lemfoerder would need a 2.2-2.9mm shim between the two inner metal bushings . I made the shim from 3x0.84mm washers (2.52mm). This gave me total of about 83.22, for 0.22 slack.
With this installed, I test drove the car. No rubber squeaking or groaning. Steering feels light. None of the clicking sounds I have been chasing down when making slow sharp turns, but will test for several more days before declaring that a win because lube may be helping.
BEFORE:
Kind of poor video, but you can sure hear clicking and groaning. Watch the metal plate at the bottom of the upper sleeve - it is inside the dust cap but is separate and firmly clamped to the chassis tube. it should not move. But it does!
https://www.dropbox.com/s/capjb5omfrow5d0/Idler%20noise.mp4?dl=1
AFTER
Groaning noise in this video, taken after repair is coming from the steering column, not the idler. Not noticeable when driving. In this video, I marked the relative parts. It shows that the upper and lower rubber bushings are not turning in the chassis tube. Clicking (likely caused by the metal face of the rubber bushing rotating against chassis tube) is now gone.
https://www.dropbox.com/s/p26q9bz1jd9aev3/Idler%20noise%20after%20repair.mp4?dl=1