# Bad brushes after 25K mi?!?

**URL:** <https://community.cartalk.com/t/bad-brushes-after-25k-mi/38932>\
**Category:** Maintenance/Repairs\
**Created:** [November 2, 2009, 3:52am UTC](https://community.cartalk.com/t/bad-brushes-after-25k-mi/38932 "2009-11-02T03:52:39Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![meanjoe75fan](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/meanjoe75fan/32/552_2.png) [@meanjoe75fan](https://community.cartalk.com/u/meanjoe75fan)\
**Post date:** [November 2, 2009, 3:52am UTC](https://community.cartalk.com/t/bad-brushes-after-25k-mi/38932/1 "2009-11-02T03:52:39Z")

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So, recently my Contour has been acting up, electrically. The “failure mode” is that the alternator is either working normally or not at all. Mostly random when it comes + goes, but more likely to not work just after start-up.  
  
  
  
 Since I’ve already replaced the brushes once–at 98K mi–I recognized the failure mode: sure enough, the brushes were worn past the wear indicators.  
  
  
  
 Now, I’m happy to learn $8 and 45 minutes were all it cost me, but is it reasonable to expect brushes (even aftermarket ones) to give up after 25K? Is it possible this indicates some other problem?

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**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\
**Post date:** [November 2, 2009, 3:57am UTC](https://community.cartalk.com/t/bad-brushes-after-25k-mi/38932/2 "2009-11-02T03:57:06Z")

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??maybe loose bearings causing rapid brush wear??

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**Author:** ![Xebadaih](https://avatars.discourse-cdn.com/v4/letter/x/d07c76/32.png) [@Xebadaih](https://community.cartalk.com/u/Xebadaih)\
**Post date:** [November 2, 2009, 4:56am UTC](https://community.cartalk.com/t/bad-brushes-after-25k-mi/38932/3 "2009-11-02T04:56:15Z")

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$8 and 45 minutes every 25k miles isn’t that bad is it?

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**Author:** ![ok4450](https://avatars.discourse-cdn.com/v4/letter/o/e9bcb4/32.png) [@ok4450](https://community.cartalk.com/u/ok4450)\
**Post date:** [November 2, 2009, 5:48am UTC](https://community.cartalk.com/t/bad-brushes-after-25k-mi/38932/4 "2009-11-02T05:48:39Z")

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There’s 2 parts to this. One is the brushes, the other is the armature commutator on which the brushes ride.

Replacing brushes without servicing the commutator is a crap shoot at best and servicing the commutator means a complete alternator overhaul; or it should.

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**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\
**Post date:** [November 2, 2009, 4:44pm UTC](https://community.cartalk.com/t/bad-brushes-after-25k-mi/38932/5 "2009-11-02T16:44:29Z")

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Pull the brushes and look down in the hole(s) at the slip rings (alternators don’t have commutators). If they don’t look smooth that’s your problem.  
You might have luck polishing them with emery cloth.