Alternator condition : how to test or evaluate ?

[Louis-Alain Richard]

HI everyone,

 

In my mind, an alternator is a on/off binary device : it works or it
doesn't. 

 

Now, I have a fresh Bosch voltage regulator in an old alternator, and I'm
not convince that this unit is working 100 %. When under load, the sound it
makes it rather shrieking, like if there was something rubbing inside it.

 

I do have a recent battery, but when I do charge it with a 110V charger,
it's a lot stronger (from the sound of the starter motor) but after a few
weeks, it drops to its "normal" level.

 

So my question is : will a rebuilt alternator keep the battery fully charged
better than the old semi-rebuilt alternator ? Besides the voltage regulator,
what are the other bits that can go wrong in an alternator ?

 

Thanks in advance,

 

Louis-Alain

1983 Quattro with a stock 90A Bosch alternator.