From my experience. The brushes in the Toyota alternator last between 180k to 200k miles as an average. This has been fairly consistent from the 1980s.

So if I make it to 200k on an alternator brushes I am happy. Starters brushes run fairly close to the same lifespan from what I have seen. Granted, lots of dirt 4 wheeling and climate differences may effect this. So keep in mind this would be western PA climate estimates.

Sent from my SM-J337V using Tapatalk

A quick follow up on this:

I installed the new OEM brushes in my spare alternator. The two JIS screws that hold the brushes down were rusted in place and even though I specifically bought a JIS screw driver for this repair, they both still stripped out. I had to dremel a slot into the screws and use a large flat head screw driver to get them out. I believe the heat from grinding on them helped in their removal.

I installed the "rebuilt" alternator in my truck and voltage does not drop like it used to. In fairness, there could have been something else going wrong with the original alternator.

When I'm in drive at a stop with just about everything on (ac, lights, stereo turned up, fan on full send etc), it sits around 13.3v where before it was dropping below 12v. I also cleaned up all of the battery connections and the connection at the alternator but they were all pretty clean to begin with.

The old brushes on the 200k ish OEM alternator were just about gone.

Yes I never seen an alternator go much over 200k on brushes. Mostly 180k to 200k is the limit. Explains why your voltage was dropping.

Thanks for the follow up as its good to see issues fixed.

Sent from my SM-J337V using Tapatalk

hi, digging up an old thread here, but i had an intermittent voltage dip occur today when i came to a stop, voltage dropped down to what looked like close to 10V. a little rev of the gas and it jumps back up to normal, but.... i wanted to ask if anyone experienced the engine stumbling at little, because as voltage dropped with RPMs dropping, it idled at what looked like 300-350 rpms, thought it was gonna stall. i think my 214k mi alternator is done!

thanks

This last summer (2021), my alternator started gradually running at higher than normal voltage (14.2 instead of 13.7, etc). Then, on the way to work one day in November, the voltage started going way low (12.5, 12.8, etc), especially when idling. Next morning, i swapped in the Denso reman'd alternator that I had purchased about a year before, and everything is totally normal again. Did not have super low idle or misfire, however.

I suspect the brushes are done along with possibkr voltage regulator getting ready to go. [ all within the alternator]

I had the bat light come on or flicker before it failed several times.

At 10v I suspect the truck was shutting down to low power. The system is designed to run around 12.8 to 13.8vlots..

Extremely lucky it didn't stall.

Sent from my SM-A505U using Tapatalk