Question = a) where stated in write up, "thread the new pieces on the existing headlight adjustment white screw", is the cutting of the new threads necessary on the new piece done by the screw with the 10mm nut (that can also be turned by the white adjuster screw but not advised), at the direction shown in following picture?
Answer = correct. I turned the 10mm black nut clockwise(below the white adjuster knob) to thread the new piece on the threaded rod inside the chassis. The new piece did not look like it was threaded, and it required some torque to run all the way up to the end. Do not use the white knob to do this, the teeth cannot take the stress. Once you have run the piece back and forth a few times, the white knob will handle all future adjustments.
Question = b) In the following picture, how are the A and B adjustments affect the proper alignment of the headlight?
Answer = (A) seems to be the main adjustment for height. I think (B) is for the high beam as it did not seem effect the low beam pattern. I never had the high beams on when I set the lows, so I am not sure. I could not find any info in the owners manual on headlight adjustment procedures. Maybe someone else will chime in with additional info.
2002 540iA Sterling Gray
1999 540iT (retired)