I have an "alternate" plan. Instead of going to the trouble to replace the whole alternator, it should be possible, and Much easier and cheaper, to replace only the brushes, which might solve your charging problem. I believe there is a little access hatch to allow this without complete remove and replace. Last year, my 90 Teg's charging light came on during a short trip, the battery died before I could get home and I had to get it towed. My great local shop charged $150 to install a new set of brushes and I've had no trouble since.