Alternator

[Alfdude1]

I have a 1999 Explorer Sport with the 4.0 SOHC. I would like to know the approximate lifespan of the alternator brushes. I would like to replace them before they fail.
Mike

 

[Gadget X]

That actually depends on a lot of factors. There is wear occurring on the brushes anytime the engine is turning, so if you let your vehicle idle a lot, there will be more wear. That being said, I've got a 94, that i always warm up before driving, with 280000 miles on it running the factory original alternator just fine.

 

[BrooklynBay]

Welcome to this forum! The previous owner of my 1995 van installed a remanufactured alternator. The alternator stopped charging shortly after I got the van. The brushes were slightly worn but not enough to cause any issues so I reinstalled them. This was a long time ago (maybe 7 or 8 years ago). Sometimes dirt could cause them to bind or not make contact. You could remove them to check their condition if you're concerned about them but I don't think that it's necessary if you're not having any issues.

 

[Alfdude1]

Thanks for the replies!! I was just wondering if I should be on the lookout since it has 166,000 miles on it. Presently everything is working fine.
Mike

 

[BrooklynBay]

A new set of brushes is a few dollars so you could keep them in the glove compartment as a spare just in case you need them.

 

[DjDom]

To be honest, a lot of factors affect an Alternators lifespan.
My original alternator lasted me 15 years. I replacement crapped out on me yesterday, lasted just over 2 years. Build quality matters a lot as well.

 

[imp]

Worn Out Brushes

Assuming no other issues affecting this situation, I've seen well-worn brushes cause symptoms of lowered charging current, where demand for power is high. This has nothing to do with battery condition, but rather the total electrical load imposed on the alternator.

Evidently, worn brushes still contacting the slip rings may cause a drop in the alternator's ability to produce power, thus, lowering output voltage.

To answer your question, yes, I'm a "worry-wart", and knowing how things interact with one-another, given your situation, I would replace AT LEAST the brushes, and AT BEST, both bearings, too. Or, the whole damn alternator! imp