5000CS Overcharging problem

[Ben]

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This will be my first post to the list.  I have been reading it for about a=
 year and currently own and maintain two Audis. An 87' 5000tq and 4000CS, b=
oth fun cars.   Lost of good info here and I hope to contribute any of my l=
imited knowledge.

My 87' 5000CS has been having some charging problems.  Ever since I bought =
it in the spring, the battery and parking brake light would come on dimly u=
sually when the headlights were on.  I replaced the regulator and brushes, =
but this didn't help.

Next I swapped the alternator with a working one from my parts car and put =
the new regulator in it.  This seemed to solve the problem for about a week=
.  Next the batter volt light started lighting up and I discovered that my =
volts were up around 17 when the car was idling.  Doh this isn't good.

I have since tried putting the original regulator from the parts car in it =
and have also swapped out the battery for a good one and still have the sam=
e overcharge problem.

I have heard that these alternators are bullet proof and 80% of the time it=
s just the brushes or regulator that go.  How could I have two bad alternat=
ors in a row?  Any one have any ideas for either alternator?  Could somethi=
ng be causing the regulators to blow?

Thanks in advance for any help.

Ben