Thank you folks - with your help I have now made some progress!
I soldered the wire that went from the choc block to earth into the wires going between pin 1. With the multimeter positive probe joined to that wire in the choc block and the negative probe to earth I finally got the expected readings, 1.65v and 0.66v. On the N/S/R I very slowly rotated the wheel, marking the step down to 0.66v when it occurred. I ended up with evenly spaced marking all the way around. I tried rotating the wheel more quickly (still very slow but as quick as I could to still read the change in voltage) and the readings all aligned with the markings I made. I did this a couple of times and it all appeared to be correct and as expected.
I then tried the O/S/R, I got 1.65v again but when rotating the wheel very slowly, no change. I tried spinning the wheel faster and at times the reading would fluctuate by 0.1-0.2v but not by the ~1v expected.
So I am certain that the problem is the O/S/R bearing, as I also have a vibration which has been coming on at lower speeds then before, from about the same time that the intermittent ABS (Antilock Braking System) issue started. Plus drone/noise. Next step is to strip it down and see how things are.
I soldered the wire that went from the choc block to earth into the wires going between pin 1. With the multimeter positive probe joined to that wire in the choc block and the negative probe to earth I finally got the expected readings, 1.65v and 0.66v. On the N/S/R I very slowly rotated the wheel, marking the step down to 0.66v when it occurred. I ended up with evenly spaced marking all the way around. I tried rotating the wheel more quickly (still very slow but as quick as I could to still read the change in voltage) and the readings all aligned with the markings I made. I did this a couple of times and it all appeared to be correct and as expected.
I then tried the O/S/R, I got 1.65v again but when rotating the wheel very slowly, no change. I tried spinning the wheel faster and at times the reading would fluctuate by 0.1-0.2v but not by the ~1v expected.
So I am certain that the problem is the O/S/R bearing, as I also have a vibration which has been coming on at lower speeds then before, from about the same time that the intermittent ABS (Antilock Braking System) issue started. Plus drone/noise. Next step is to strip it down and see how things are.
