So last week I noticed that my voltmeter was showing fluctuations from 11.6v to 12.7 while I was driving. Didn't matter what RPM or electrical load. I tested it with my multi-meter and it was fine. Just an instrumentation problem, no biggie.
But now I'm wondering if i'm due for brushes. If I turn everything off it's at around 13.9-14.1V, but with the headlights on it's down to 13.5, and if the blower's on high, it drops to 13.1 or so. Now I'm measuring this at the lighter socket in the dash (cause I'm lazy and didn't want to go back and forth every time I wanted to read the meter).
It's the original alternator and brushes as far as I can tell, 230K miles on it. There's no real problem other than the headlights getting a little yellow/dim when I turn the fan on, or roll a window down/up. I feel like I'm paranoid cause I wouldn't even have noticed if it wasn't for the bad meter originally.
So do I get the new brushes/regulator, or is this all typical for these cars?

Thanks again to all you Brickboarders