Replacing voltage regulator rather than entire alternator: Did I decide correctly?

[myf16]

The dash warning battery symbol lit up and my 1996 Explorer's alternator stopped generating anything. I went through the troubleshooting procedure in the service manual to the point where you ground the field coil terminal and sure enough the alternator sprang to life with good output and a slight dip in idle rpm. The service manual says to replace the voltage regulator.

FWIW I also checked the 7.5 amp field coil fuse, number 15. It's fine.

I then had the choice of paying $75 for a new complete alternator or $20 for a new voltage regulator with brushes (from ebay). I figured that my factory alternator with 110k miles should last as long as a new cheapie alternator. Is that completely wrong?

I guess the good news is that it's so darned easy to remove and replace the alternator on this vehicle. The other factor in my decision was that I could get the regulator in 2 days rather than 4 days for the complete alternator. Those regulators are so small they can go by priority mail or even regular first class.

Please fire away on what decision you would have made. I promise to post here if and when the repair fails.

 

[Goldmaster]

As long as replacing the regulator solved your problem, I'd say you decided just fine. Most of the parts store alternators are a crap shoot with shoddy workmanship anyway. You'd probably be better off having yours rebuilt locally whenever the time comes. But if you do decide to go with a parts store rebuild someday, just hang onto your bad regulator (if you haven't tossed it) to pop back on it when you exchange it. That way you can keep the new one you just bought for a spare.

 

[waskly]

i have not seen a part store sell an alternator with out a core charge.

 

[my98nnj]

Put new bearings in it and you'll be set for another 100k miles.

 

[budwich]

As you said.... $20 versus $75... IF it doesn't work out, your total cost will be $95 versus $75 if you have to "backtrack".... not worth fretting about... especially as you say... the alternator is so darn easy to remove... so you can do it as many times as you want...

 

[desertsky]

i have not seen a part store sell an alternator with out a core charge.

Most parts store counter guys probably wouldn't check to see if the regulator was in it when you return the core!

 

[drdoom]

Good diagnostic skills, I agree with you. So much inferior parts on the market, might as well fix it yourself...more of a known quantity.

 

[koda2000]

Put new bearings in it and you'll be set for another 100k miles.

+1 only other thing you should have done

 

[FIND]

The rest of the alternator will generally last twice as long as the regulators. In the future, if it goes bad again in the life of the truck, replace the brushes and bearings too for only another $20. It will be as good as a reman.

 

[96eb96]

i have not seen a part store sell an alternator with out a core charge.

NAPA new alternators have no core charges. Sometimes they are priced close to the reman ones. Rockauto has some like that too.

 

[wa3ra]

If you can find a master rebuild kit, for around $30-$35, it will have the regulator, brushes, diode bridges, and bearings.

I've taken to keeping a spare alternator on hand for most of my vehicles; a $10 boneyard pull, a cleaning, case painting, and rebuild sets you back under $50, and the peace of mind is priceless!

 

[myf16]

The rest of the alternator will generally last twice as long as the regulators. In the future, if it goes bad again in the life of the truck, replace the brushes and bearings too for only another $20. It will be as good as a reman.

Thanks for all the helpful and encouraging posts.

How much work is it to replace the bearings? I assume you have to remove the pulley somehow, but do you need to open the case?

Also, do the bearings fail slowly and noisily, or quietly then suddenly?

I am replacing the brushes, but I didn't know that bearings were available separately.

I plan to complete this repair Friday or Saturday.

 

[FIND]

Here's a video for replacing brushes. You don't need to take apart the whole alternator to do it. Bearings are probably not an issue for you at this point. Rebuilders replace them every time, but they would probably outlast 2 or 3 sets of brushes unless you are getting a lot of water or other crap in your alternator.



Brushes are super cheap too. No reason not to do them when you replace your regulator, aside from the fact that you can't buy them at many parts stores anymore (Sturdevants, a store in my area carries them, but many other stores don't). Master rebuild kits are stupid hard to find. Even replacement diode bridges are hard to find... seems like those kinds of things are only sold in bulk these days... Kinda a go figure... Most people don't rebuild things like that. Hell, most people don't even change their own oil.

If you do ever take apart your alternator all the way, be careful when doing so. But, to take the pulley comes off easiest with an impact wrench to remove the nut, otherwise you have to hold the pulley while using a wrench on the nut, which is hard to do. Then there are only a few long bolts that hold the case together, but they are pretty small diameter... Something like 1/4 inch or something... I can't remember, I rarely think about that kind of thing. Then it is mostly pressure that holds everything together, but there is a clip behind where the pulley goes on. You will need a press or to be careful when hammering the shaft out of the front part of the case. The back part of the case will come off with a little elbow grease and the windings come right out from it.

 

[dcdyd]

I am getting P0340 code but the truck runs fine. I cleared the code once and it came back after weeks. At this moment I am wondering whether it is the CAM position sensor or the alternator. The voltage measured at the battery terminators are fine withing the range for both when engine stopped and running. Any suggestions whether it is alternator?

 

[2TimingTom]

I bought a rebuild kit for my Saturn S-series. I watched some videos and read some how-to's. Mine wasn't as easy as the videos and how-to's suggested. And I consider myself fairly handy in the garage. I actually gave up on it- I couldn't get the back part out (where the brushes and whatnot are). I put it all back together the best I could and got a remanufactured one from Autozone.

You mileage my vary, but I'd skip the rebuild and just replace it.

 

[FIND]

I bought a rebuild kit for my Saturn S-series. I watched some videos and read some how-to's. Mine wasn't as easy as the videos and how-to's suggested. And I consider myself fairly handy in the garage. I actually gave up on it- I couldn't get the back part out (where the brushes and whatnot are). I put it all back together the best I could and got a remanufactured one from Autozone.

You mileage my vary, but I'd skip the rebuild and just replace it.

FWIW, that was a Saturn...

But yeah, sometimes you run across ones that are just going to fight you till you die or give up.

 

[desertsky]

Thanks for all the helpful and encouraging posts.

How much work is it to replace the bearings? I assume you have to remove the pulley somehow, but do you need to open the case?

Also, do the bearings fail slowly and noisily, or quietly then suddenly?

I am replacing the brushes, but I didn't know that bearings were available separately.

I plan to complete this repair Friday or Saturday.

Bearings usually fail over time due to loss of grease. They start whispering and then transition to growling and sometimes squealing. The front bearing is under a lot of load due to bent tension and driving forces. If I ever take mine apart, i will measure the bearings and offer them on my site.

 

[myf16]

The rest of the alternator will generally last twice as long as the regulators.

I hope so. I completed the repair easily this evening. No more battery warning light. I think it's fixed.

BTW, the new brushes came fully retracted, held in by a thin rod inserted through the regulator. You just bolt the whole thing on to the alternator, then you pull out the rod to free the brushes to spring out toward the contact rings on the shaft. That was very slick. There's a SoCal guy on ebay selling this regulator+brushes assembly for $21 shipped, but he accepted my $20 offer. YMMV.

 

[dcdyd]

I have 98 EB and would like to do the same thing also. Can yo add the link of the eBay item you used?

 

[myf16]

I have 98 EB and would like to do the same thing also. Can you add the link of the eBay item you used?

http://rover.ebay.com/rover/1/711-5...0001&campid=5574912417&icep_item=320742969674

Note the two holes in the brushes in the photo. The pin goes through the regulator case and through those holes in the retracted brushes. After you install the part you pull the pin to free the brushes to spring out.

Edited to add: When you remove the old regulator, do not unscrew the two central torx screws! Otherwise your nuts will fall into the armature. That's painful. Only the 4 outer screws attach the regulator to the alternator.