Hit your Alt with a hammer and that may get you bye until you can change the brushes.


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So I replaced the brushes, got the alternator back in, and noticed the light was still on... scratching my head I started checking voltage and noticed it was dropping quickly, worse than it had before. I thought maybe I finally shook something loose 100% and now the alternator was toast. I go to the only parts store near me that had a carquest alternator in stock which is about an hour round trip. I get back, start to take the OEM alternator back out and notice the belt has no tension! I look at my buddy confused because we had both checked the belt for tightness. I am able to get quite a bit more turns on the adjuster before finally reaching tension, and no more battery light! Going on 4 days now without the light coming on.

Than you guys for your help and figured I would post back on here to share my results in hope that it helps someone in the future.

I have attached a photo comparing my 310k mile brushes to a new set.

Attached Images

 

Glad to see it worked out.
Maybe this will give me incentive to yank the new brushes that reside in my glovebox and finally swap them out, at 205K I’m sure they’re needed.

It is a quick job! Was happy to be able to do it all from the engine bay and not have to pull my 4xinnovations skid off.

The biggest pain in the butt for me is pulling the connector out of the back of the Alt.

I also have an amp gauge on my SR5.


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I undid the connection after I had the alternator free from the brackets. Was 100% easier. I have done it both ways and while the alternator is attached to the engine, it took two people to pry it off lol

Good to know as I’ve heard that’s the most difficult part of the job

Yep. I have an offset jaw pliers that I use to grab and squeeze the locking tab.


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Always looking for excuse to buy new tools.
Got a picture or link for the offset pliers you use or just a basic pair of offset needle nose?

In a correctly operating charging system, the batt voltage should not change with revs, right?

That's correct.

If you’re in gear with the brake on idling at 600rpm your Alt is only capable of pushing 40a. Any amp draw over that will cause the battery voltage to drop until the engine goes to a higher rpm.


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I’ll try to keep it short and sweet.

Never had power issues prior and with no changes.
Drove normally Saturday, let sit Sunday, then Monday morning battery light came on 5 minutes down the road, lights dim/stereo turned off/blinkers cut off.

Jumped battery voltage idling around 7-8, same as alternator

New battery/same alternator, idle around 11.9 - 12.1 and 12.2 with engine off; no battery light day of install

Next morning, light back on with same voltages, battery light turned off after 15 minutes of driving, turned off for 9 hours, then light was back on for 5 minutes or so.

Is this signs of a failing alternator?

I think you need an alternator

Yes, of course. The battery light means the battery voltage is low, not that you have a bad battery. Get a Denso alternator (rebuilt by Denso) or risk a crappy replacement.

Also, you just killed the life of your new battery running it with a bad alternator... get a charger on it and don't leave it discharged like that.

-Charlie