Alternator
 

On a typical Bosh alternator (70s, 80s), is it normal to have just a little bit of solder on the edges of each side of the commutator (the part upon which the brushes ride)?

The brushes are not riding on the solder.

Also, the bearings seem fine and yet a slight clunking can be felt when you turn the pully by hand. Is this normal? It´s a newly rebuilt alternator.

"Klunking"
 

NOT GOOD,especially with "Hand Turning"!
Under Load there's much more stress...And thousands of RPMs.

The "Solder" is probably the result of refitting new "Slip Rings" on the Shaft.
The "Brushes" ride on the "Slip Rings" which are a "Maintenance" item.

The real question is did the ReBuilder "True Up" the New Slip Rings on a Lathe?
(Or even replace the Bearings?) [Klunk,Klunk]

Typical "Big Box" type [Autozone,Advance ,Pep Boys,Etc.) "Reman" supplier
is a "Spray and Pray" operation.They clean and spray paint the Alternator...
Then Pray it works for the length of the warranty.

Two different approaches to Bosch rebuilding:
1.Total Reman:
Oichan's Corrado Alternator Rebuild.

2.Bearings:
Alternator Bearing Replacement in a W140 Mercedes

Wagner Alternator will have ALL the Parts you need:
Wagner Alternator and Supplies, Inc.

Should spin pretty quiet. I suspect a bad rebuild. I've seen some pretty useless "reman" parts. Almost as if they put it in a parts washer and painted it, sneezed some grease in it, and slapped a shiny "remanufactured" sticker on it.

You guys have confirmed my suspicions. Thanks