In addition to checking the brushes, you also want to check the bearings.
The rear bearing fails fairly frequently.  This causes the brushes to loose
contact.  With the belt removed, check the pulley for side to side play.  If
any, the bearings are wiped.

Dennis
-----Original Message-----
From: Bob O'Shaughnessy <oshaug@INFINET.COM>
To: Vanagon@GERRY.SDSC.EDU <Vanagon@GERRY.SDSC.EDU>
Date: Monday, December 08, 1997 9:03 AM
Subject: Alternator out at *high* rpms?

>     Took two nice little trips this weekend in the snow and in the dark
>and had a weird electrical glitch.
>
>     At whatever rpms translates in to @50mph in 3rd and @70 in fourth,
>my alternator and oxygen sensor lights flickered on.
>     I'm a bit worried about electrical output at all rpms, as I noticed
>that while cruising at 65 the dash lights were dim, and the fuel and temp
>gauges were reading a bit low (note to self on road:  get electrical
>gauges for project van).  Oddly enough, if I let the engine cycle down
>towards idle (clutch in, foot off of gas pedal, goin' downhill) something
>went right, and the dash lights got a notch brighter and the temp gauge
>moved back to its normal range.  When I took the engine back up to speed
>to maintain 65, it all dims again.
>
>     The belt is okay (I checked and re-tensioned it before the trip)  so
>I'm going to take the brushes/volt regulator out to have a look later on
>tonight, am I headed in the right direction?
>
>_________________________________________________________
>
>Bob O'Shaughnessy
>84GL, 85GL project (Now Running!!! Waiting for tags!) (Mine)
>82 Diesel L with carbed Rabbit engine (belongs to friend)
>74 Bus (Dad's)
>72 Wife, 94 Rabbit, 95 Cat, 96 cat.
>