Alternator failure....or just about

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Taking the family on a camping trip today about 4 hours from the house. Truck ran perfect all the way until literally 200 yards where I turn off of the main trail onto a side trail to our camp site....battery light comes on, volt meter between half and 3/4. Well s***.

I decide to bail because I figure it's the alternator and I know I don't have long before the battery dies. We were about 30 minutes out of town so I hauled ass down the trail. Whole time volt meter is slowly dropping, ABS light comes on, then AHC pump won't come on to bring the truck down from high, then radio starts cutting off and I'm getting reeeeeal worried. We made it back to the main road, and once up to speed the volt meter goes back to normal (3/4 gauge) and I make it to auto zone.

He tests the alternator and voltage tests good, but battery tests bad. The battery was in the truck when I bought it (Delstar) and I don't know how old so I buy a new one.

All is well, no battery light, charging well. I talk my wife into trying again, probably was a bad battery and after all we are already up here.

Once we get about 2 miles out of town at a stop sign I notice the volt meter drop a tick down then back up a couple times quickly...never seen that before so I say we bail again. 10 miles down the road the light is on again, but staying just between half and 3/4 on the gauge. We made it about 100 miles like that with the battery light on and going through a town it starts dropping quickly again...ABS light, dim head lights, radio flickering. We were at at stop light so I put it in neutral and revved it to around 3k for about 10 seconds. Volt meter jumped back up and she drove the 50 miles home with no battery light all normal.

No record of an alternator change in it's history so I figure 186k miles is pretty damn good run. I'm just glad she got us home.

I'm thinking about maybe doing the alternator and starter at the same time as PM.

Is our only option reman'd Denso?
 
I’d say your gut feeling is spot on: alternator. Reman Denso or new unit from Toyota, the latter of which is $$$
 
I’d say your gut feeling is spot on: alternator. Reman Denso or new unit from Toyota, the latter of which is $$$

Is it worth trying to replace the brushes?

Will the Toyota part number work on the 1999 LX470 (27370-75060)
 
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Is it worth trying to replace the brushes?

Will the Toyota part number work on the 1999 LX470 (27370-75060)
Yes, But if you’re going to replace the brushes ($15 from Toyota), it would be wise to also replace the bearings ($25 from Toyota) and test the voltage regulator. If the regulator is bad, it’s $90 from Toyota.

If you decide to buy a new (or reman) alternator, here’s part number for the 100 amp version: 2706050260
 
Yes, But if you’re going to replace the brushes ($15 from Toyota), it would be wise to also replace the bearings ($25 from Toyota) and test the voltage regulator. If the regulator is bad, it’s $90 from Toyota.

If you decide to buy a new (or reman) alternator, here’s part number for the 100 amp version: 2706050260

Thanks, it isn't making noise right now and I don't have a press so I may just swap the brushes. I suspect the voltage regulator is fine because in my experience when they fail they let too much voltage through, but obviously I could be wrong about that. What way would you test it on the bench?
 
Thanks, it isn't making noise right now and I don't have a press so I may just swap the brushes. I suspect the voltage regulator is fine because in my experience when they fail they let too much voltage through, but obviously I could be wrong about that. What way would you test it on the bench?


You can't reliably test an alternator with an 'intermittent' problem. If you go the route of replacing the brushes then do the Voltage Regulator too. Also check your wiring and connector.
 
It’s such a pain to change just put a new one in and forget it. Don’t mess around with taking it in and out trying different parts.
 
It’s such a pain to change just put a new one in and forget it. Don’t mess around with taking it in and out trying different parts.

I would normally, but all the threads I've read about people swapping in a new one that fails within a year im scared to.

Seems like most had better luck replacing the brushes in the OEM unit
 
Yes, Just OEM brushers are the way to go. My 92 Sprinter got 278K miles, 97 4Runner 216K miles and LC 238K miles with original alternators with a fresh brush kit. Nothing else have been replaced.
 
Yes, Just OEM brushers are the way to go. My 92 Sprinter got 278K miles, 97 4Runner 216K miles and LC 238K miles with original alternators with a fresh brush kit. Nothing else have been replaced.

Good to hear, I ordered my brushes today from Toyota parts deal (my local dealer didn't have them).

I'm hoping it doesn't end up being the regulator and I have to take it back apart, but I'd rather not spend an extra $150 right now if I don't have to.


I just went and checked the tension on the belt since I read somewhere that could possibly cause intermittent charging issues if it's too loose. Belt seems ok I guess, I can't twist it all the way around...not sure how tight it should be.

My negative batter cable has some very slight green on the end of the cable. Truck cranked no problem and battery light was not on, charging voltage at 3/4 mark on gauge
 
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I would normally, but all the threads I've read about people swapping in a new one that fails within a year im scared to.

Seems like most had better luck replacing the brushes in the OEM unit

Well that may or may NOT solve your problem. IF I had done that with mine....I would have been pulling it out again in short order. Mine had a gritty rear bearing, and the regulator had gotten so hot it had started to melt. Yes, 'some' folks get away with just brushes....but it's always better to take the alternator out and thoroughly inspect it.

I cringe every time I see a post saying "all it needs is brushes". That can't possibly be universally true....as too many variables exist. Also consider WHERE your alternator lives (right down at the bottom of the engine, subject to every containment able to reach it). Either pull it with the idea that YOU will rebuild it to whatever extent it needs, or just replace it with the best quality reman you can find.
 
I’d say your gut feeling is spot on: alternator. Reman Denso or new unit from Toyota, the latter of which is $$$
In my opinion, the Toyota part isn’t that much more $$$ than the Denso. I replaced mine this summer, and the Toyota part (from the dealer) was $190 plus (IIRC) a $60 core charge.

The 100A Denso was about $145 plus $30 shipping. So, definately cheaper to the tune of about $80. The kicker was, the Denso was 2 weeks backordered, but I was able the Toyota part next day out of Kansas City. Compared to what some of the parts on this truck cost, not so bad!
 
Well that may or may NOT solve your problem. IF I had done that with mine....I would have been pulling it out again in short order. Mine had a gritty rear bearing, and the regulator had gotten so hot it had started to melt. Yes, 'some' folks get away with just brushes....but it's always better to take the alternator out and thoroughly inspect it.

I cringe every time I see a post saying "all it needs is brushes". That can't possibly be universally true....as too many variables exist. Also consider WHERE your alternator lives (right down at the bottom of the engine, subject to every containment able to reach it). Either pull it with the idea that YOU will rebuild it to whatever extent it needs, or just replace it with the best quality reman you can find.
I agree with you completely. Oddly enough, my alternator was in practically identical condition as yours - rear bearing was completely shot, front bearing was near dead, and the regulator was burnt to hell, BUT the brushes still had some life left in them. Replacing just the brushes would’ve had a negligible effect on the performance of my alternator.
 
In my opinion, the Toyota part isn’t that much more $$$ than the Denso. I replaced mine this summer, and the Toyota part (from the dealer) was $190 plus (IIRC) a $60 core charge.

The 100A Denso was about $145 plus $30 shipping. So, definately cheaper to the tune of about $80. The kicker was, the Denso was 2 weeks backordered, but I was able the Toyota part next day out of Kansas City. Compared to what some of the parts on this truck cost, not so bad!

Where did you get the whole Toyota alternator for $190? Online the regulator only is like $150. Alternator is $556
 
In my opinion, the Toyota part isn’t that much more $$$ than the Denso. I replaced mine this summer, and the Toyota part (from the dealer) was $190 plus (IIRC) a $60 core charge.

The 100A Denso was about $145 plus $30 shipping. So, definately cheaper to the tune of about $80. The kicker was, the Denso was 2 weeks backordered, but I was able the Toyota part next day out of Kansas City. Compared to what some of the parts on this truck cost, not so bad!
Hate to tell you this, but you just paid $45 more for the reman Denso with a Toyota sticker on it. Pricey sticker! A *new* Toyota alternator is $600-700.
 
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Where did you get the whole Toyota alternator for $190? Online the regulator only is like $150. Alternator is $556
It’s a reman that is Identical to the Denso reman, but has ‘Toyota Denso’ on the sticker rather than just ‘Denso’. Toyota 270605026084 = Denso 2100565.
 
Hate to tell you this, but you just paid $45 more for the reman Denso with a Toyota sticker on it. Pricey sticker! A *new* Toyota alternator is $600-700.
No doubt. It is clearly marked Toyota Remanufactured Parts on the box. But, the “generic” Denso reman was two weeks backordered. So, $45 seemed like a reasonable tax to get it the next day.
 
Where did you get the whole Toyota alternator for $190? Online the regulator only is like $150. Alternator is $556

Can you share your online source for the regulator?
 

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