so i replaced my 89 civic's alternator this weekend [nearly 160k miles]
and thought it would be good to pass a few things onto the group.

1. you /do/ need to remove the driveshaft! don't waste time messing
about. if you go straight there, it's quicker and simpler than messing
about "trying to find a way". because there isn't one.

2. mitsubishi alternators are unmaintainable. just toss it and get a
nippon denso. i got two good ones [newly refurbished] from my local
junk yard for $15 each plus $5 core. mitsubishi internal componentry is
much inferior - bearings, brushes, slip rings, rectifiers. better than
bosch [maybe] and lasted ok, but just not in the came construction
quality league as denso.

but here's the real kicker:

3. had noticed the usual pre-failure symptoms - dim lights, slow to kick
in after starting, etc., hence replacement before complete failure. but
it also completely cured another seemingly unrelated problem. when
started, and allowed to roll, my car would speed up and slow down
repeatedly from idle, just like the symptoms of low coolant affecting
the tw sensor. i'd spend a couple of months idly speculating about this
and had bled the coolant system a couple of times to no avail. but with
the new alternator, this problem disappeared immediately. now i figure
that the electronic load detector [eld] was detecting low current and
boosting revs to kick up output from a weak alternator. now, with a
good alternator with new brushes, electrical output is strong from idle,
so no need for the eld to raise revs, hence problem solved.

ymmv.