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Discussion Starter #1
So, I'm in the process of making a bunch of repairs to my car and in the process I'm removing and inspecting parts that I can verify the condition of, even if they appear to be functioning properly.

With this being said, I removed the alternator on my car and took it apart to see what sort of condition it was in. Well, the brushes were nearly worn out and the slip ring had pretty deep grooves in it, so I went on and bought a kit and replaced those parts along with the bearings.

I did not replace the rectifier because the alternator was charging before I removed it from the car and my thought process was just to replace what was worn in the alternator.

When I separated the stator/rectifier from the case, I noticed that two of the stator wires came off of the rectifier, so I cleaned them up with a steel brush and re-soldered them back on. The other 4 wires were still attached.

So in total, this is what I have done to the alternator:

-Replaced Voltage Regulator/Brushes
-Replaced Front and Rear Bearings
-Replaced Slip Ring
-Re-soldered two stator wires to the rectifier (they came apart during the removal of the case)

As far as cleaning, I sprayed out the stator, rectifier and rotor with CRC electrical spray. I cleaned out the case with some Mean Green and a toothbrush. Then I sanded the inside where the stator touches the case smooth with sandpaper. The alternator was quite dirty/dusty to be honest.

So, now at this point I'm feeling good and I took it to the parts store to verify that everything works and it fails the test because it's charging around 11.8 volts.

Now I'm a bit confused.......wouldn't the alternator light have come on if it was charging this low prior to the rebuild? Do you think changing out the rectifier would change anything? How do I test the rectifier?

Any suggestions/opinions? I am sort of perplexed here.
 

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Good job and good post. Can't help much cause I have never done it. Now I wanna do my own instead of farming it out. I know that rectifiers (in our Alts) do fail, and woulda been smart to replace it based on everything else you did. When they did the test, did they check for AC (not DC) voltage? I believe a failing/failed diode (rectifier) induces AC on the output. Gotta wonder and question your repair/re-solder of those rectifier wires...? you sure bout em'?
 

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Discussion Starter #3
As far as when I got it checked, to be honest, I could tell that the person that tested it had never done it before and I'm thinking about taking it to another location to be tested so I can get more details. Another person had to help him connect it and he was unable to remove the connector from the alternator after he finished the test. Also, he froze when I asked him why did it fail. The most I could get out of him was low voltage. I wasn't impressed to be honest.

With regards to the solder, I cleaned up both areas with a wire brush prior to resoldering. I thought that was straightforward.

What I'm going to do this evening is take it to another spot to see if I can get better details and probably order a rectifier and give it another whirl based on what I see this evening.

Edit: I went on and ordered a new rectifier for it. It should be here by Friday hopefully. In the meantime, I'll disassemble the alternator and wait until then.
 

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Gotta wonder and question your repair/re-solder of those rectifier wires...? you sure bout em'?
With regards to the solder, I cleaned up both areas with a wire brush prior to resoldering. I thought that was straightforward.
Sorry man, not meaning to criticize your work. I would question or wonder about my own work if in your shoes. As you likely know, soldering can sometimes go wrong. like a cold joint, and for different reasons.

Please share info you have on what/where you got your parts & rebuild kit. I might be in the market soon. No, I haven't searched the interwebs yet. Cheers!
 

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Probably the solder job, wire brushing not good enough there, even sand paper and all looking clean may not be. You test after for resistance across the solder point but being diode pack the result fools you since the other good diodes pass power through them to make your solder joint look good. Best way to check diodes like that is all leads unsoldered and can do them individually and reliable test then. Of course you then have the problem of taking loose joints that were perfectly fine, the fun of it all. At least the positive diodes must be separated electrically from the negative to properly check or one way passes power and makes you think everything is fine when it easily may not be.

How did you change slip ring?, it is part of the rotor. These can have a really worn brush contact point, I have sanded it smoother and radiused the ends a bit to allow new brushes to drop all the way to the bottom of the groove there. Elsewise the brush rides on the side of the groove for diminished output until it wears enough to drop fully down.

Next time you get alt checked ask them specifically to tell you how much RIPPLE it has, ripple is the indicator of high/low volt (AC voltage) caused by diode failure. It should be low and flat. If not something wrong in diode pack.
 

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Discussion Starter #6
Well, I finally pulled the alternator apart again this morning and I pulled firmly on the stator wires that came off the alternator and another one of them (not the two I soldered) came apart from the rectifier, so that was the problem.

With regards to how I changed the slip ring, I cut off the part of the fan on both sides that goes over the slip ring wires, cut the slip ring where the leads connects to the two terminals on the rotor and removed the old slip ring. Then I took a dremel with a wire brush attachment and polished the terminals until they had a shine. After that, I installed the new slip ring and soldered the leads to the terminals.
 

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Hey if it works.................

The most common thing I find wrong on these if not the regulator is the diode connections, commonly several can be bad, often they seem connected until you look close and see the separation cracks that makes them not connect even though they appear at first glance to be. If not melted bad often simply soldering up the broken lead can have you up and going again. I've got one like that that I fixed and been running for years after it. Quick thirty second repair, the quickest $200 I ever made.

FYI, if you carefully grind off the retention bumps on the plastic tolerance ring and then lightly grease it up to slide back in commonly they don't break when pulling alt back apart later. The bumps provide enough lockdown they then begin to break, intended to sell more parts. I generally pick a suitable sized freeze plug and flip it over on the back bearing hole and make up a short retention strap out of like 1/2"X2"X1/8" and a short bolt in the unused back hole there, the tab/strap then pushes down on the freeze plug to pin it in place over the back bearing hole, no more covers needed to cover that hole up either.
 
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