In my search for a replacement alternator, I came across one that had a pulley that wouldn't spin freely. It spun, but stopped after about one revolution. My old alternator pulley spun a lot more easily. Is the bearing too tight? Should the pulley spin fairly easily ?

Thanks

 

it's not going to spin what i'd call freely but it would spin without you feeling any tight spots as it spins. it's pretty simple job to put it on and find out if it works ok or not

 

There could be several reasons a rebuilt or even new alternator might not spin freely. As long as there is no noise while the rotor is turning, the alternator may be just fine, and the resistance could be from the seal lips of the front radial bearing, extra grease in the rear cylindrical roller bearing, and/or higher than normal spring tension on the brushes. An alternator that spins as freely "as a top" with no loss of motion for tens of revolutions may have problems, such as poor brush spring tension, no grease in the rear bearing, or worn sealing surfaces on the shaft at the front bearing.