alternator swap

[amalventano1@comcast.net (Allyn)]

the alternator (bosch rebuild, from prev owner, unknown purchase date) on the
wifes jetta is acting up. voltage goes to 12.8 on startup (actually charges
battery enough to start w/o jumping), but easily gets loaded down. headlights
and a/c are too much for it to handle, as voltage drops to the 10.5-11 range.
i've tried swapping brush+regulator assemblies with no luck. my guess is some of
the output rectifier diodes are toast and it simply cant put out the rated
current anymore.

questions:
1. this thing still has a bosch rebuild sticker on it. do they offer any kind of
warranty at all?
2. what potential differences are there between the alternators on an 87 8v
jetta (with a/c), and an 87 scirocco 8v (w/o a/c). they look the same on the
outside, but will the scirocco alternator possibly have a lower current rating,
being non-a/c and all?

thanks in advance for info,
Al

Allyn Malventano, ETC(SS), USN
87 Rieger GTO Scirocco 16v (daily driver, 180k, rocco #6)
86 Kamei Twin 16V Turbo Scirocco GTX ('it has begun', rocco #7)
86.5 Occo 16v Trailer (dotting 'i's across the country, rocco #8)
87 Jetta 8v Wolfsburg 2dr (daily driver, 260k, 0 rattles, original clutch,
driveshafts, wheels :)