the old mystery of uneven brushes in alternator

[friendly_jacek]

this is "new" used one from 2007 2.2 ecotec with 33,000 miles. brushes are 12 and 8 mm:

the "bad" old one from 2003 2.3 ecotec with 135,000 miles was similar, brushes were 6 and 4 mm. Forgot to take pictures of that one.

 

[Chris142]

Huh that is odd. I wonder if theres that much variance in the springs

 

[hotwheels]

Maybe one brush holder has dirt buildup or a weaker soring.

hotwheels

 

[HerrStig]

I don't think I have eve seen them wear at the same rate. My guess is that runout on the rotor shaft affects the outer brush more than the inner. Just a guess.

 

[HangFire]

Runout, surface finish, spring tension, it's gotta be something different between the two.