Alternator Replacement - A Saga (1 Viewer)

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As many failures I get with reman denso units from napa both alternators and starters. I'd bet on just bad luck and I'll be forking over the coin for a new unit given availability. One thing to check though after multiple failures is the charging/starting harness and engine/chassis grounds via simple voltage drop test, this can cause both battery or alternator failure. Make sure you're in spec I rarely see more than 15mV of drop on either side though most manufacturers spec out much higher.
 

94SRUNNER

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During my lunch break I pulled the cover off the latest OEM alternator that failed to see if there were any signs of visible damage.

From what I see, it appears there is some corrosion on one of the rectifier leads, which I am thinking may be the cause of the intermittent whining noise and low voltage (on the dash gauge and ScanGauge) I experienced.
IMG-6690.JPG
 

94SRUNNER

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Update -

The Denso reman'd unit I am running from NAPA has been performing well so far and have had no issues with the exception of a short period of time when the voltage was 12.7-13.0V at idle. Typically I observe idle voltage at 13.1-13.3V.

I had our local starter and alternator shop, Dayton Quality Starter, rebuild the used OEM unit on the shelf with a bad rectifier, they did a complete tear down and rebuild, included; bearings, brushes, rectifier, bead blasted the frame components, turned the comm (I'm probably forgetting something). The voltage regulator tested good so they re-used it. Cost was about $110 for the rebuild.

I plan to install this rebuilt unit when I do the radiator over the winter.
 
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Seattlw
I haven't seen new bearings in denso rebuilds, nor regulator.
rectifier yes, brushes yes. I do wonder though, and assume now, that rebuilt densos don't automatically come with a list of new stuff.
I have two. My original was not the OEM stock unit at 180k.
What I did was redo the first one while I waited on the second to arrive. By the time it did my first one was redone and better than a rebuilt denso.
I thought that's weird, but at least there's a new rectifier on it and brushes. But old reg and old back bearing. Also old brush holder.
Oh well I guess.
My only concern about mine is the non oem regulator. BUT it's been great for at least 35k miles.

I wouldn't just install a new rebuilt denso without taking the cover off and looking at it. It's pretty easy to educate yourself if you don't know anything about alternators.
Where did you buy the new components for the rebuild? I currently am rebuilding and need: rectifier, regulator, brushes.
 

94SRUNNER

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jerryb

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There's the place that Paul uses, their website seemed better but different prices for certain things. They are all different. Early alta and late alts- all different. It also seems that transpo regulators are the norm at the 3rd party websites.
 
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Seattlw
There's the place that Paul uses, their website seemed better but different prices for certain things. They are all different. Early alta and late alts- all different. It also seems that transpo regulators are the norm at the 3rd party websites.
IDK who paul is or what website he uses. Mind sharing? Thank you much.
 
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So I literally just finished typing up a step by step R and R for the alternator as I just did it twice this weekend...with help from mudders. I take out the three bolts from the PS pump and that let's it move enough. No line disconnect, or reservoir, or bleeding needed after. I too pull it out the top.
My advantage is my wife also being my co-mechanic(yes I am very lucky). The extra hands makes it much easier.

So, your sig says you have a '99, and the original post says he has an '06. I believe 99s have a 100-amp alternator, and later years have a 130 amp, and there's a big size difference. You may very well need much more room to get the later alternator out than the early one.

I do plan to pre-emptively rebuild the alt in my '99 sometime soon, and it doesn't look hard to get it out the top. I've had it dangling there before when I had the timing belt off, just need to disconnect wires and there should be room without disconnecting p/s hoses.

I have a Maniac Electric Motors rebuild kit sitting in my workshop ready to go. It's not Denso, but I've used a Maniac EM rebuild kit in my wife's Subaru several years ago, and its been working fine for years.
 

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