alternator and volt reg help!!! - Page 2 -

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post #16 of 31 Old 01-06-2010, 06:14 AM
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Both, actually. If it had been ungrounded, that might have been the cause of the problem. If that ground wire is good it should be enough, but then that means the problem is somewhere else.

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post #17 of 31 Old 01-07-2010, 09:39 AM
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Found out some news for you...

Found my parts guy that knows what a paper catalog is for, and your 35 amp generator in your '65 CJ-5 will take Advance Auto p/n R-185, this is a Borg Warner unit and will run you about $39.99

It's still in the system, but expect to order it a day or two ahead of time since it's not a 'Stock' item...
I'm sure they don't have much call for these regulators anymore!

The case of the voltage regulator needs to be grounded to the battery,
And yes, your generator will have a 'G' or 'GND' terminal on the case.

The 'G' or 'GND' terminal on the generator should connect to the 'F' or 'FLD' terminal on the voltage regulator.

Having the frame of the generator grounded to the battery is always a good thing, but the 'G' or 'GND' terminal should NOT be connected to the battery.
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post #18 of 31 Old 01-07-2010, 01:51 PM Thread Starter
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wow thats awsm i was just in advanced the other day and they tried to sell me the wrong one for 90 bucks, glad i waited.

so you think it is pretty typical that replacing this thing will fix my problem or do you think the generator will need work too. like i said i have no idea when if at all the generator was re-built. are new brushes easy to get for them if this doesnt work?

and also is there anywhere that describes how to service these volt regulators or is this new one a solid state?
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post #19 of 31 Old 01-07-2010, 02:04 PM Thread Starter
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ok just called Advanced ordered it should be 2 days. answered most of my questions. they have a mechanical one for 78 bucks but im not interested prolly just do like you said and buy one in the future if i plan to sell it to give the guy. but other than that i think this one will be better. so hopefully some new wiring a better ground and this reg will get the old girl back up and runnin.

thanks again for all your help, i prolly would have lost my mind without it trying to figure out what was wrong. or just broke down and put in a modern alternator wich would have hurt me to do,.
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post #20 of 31 Old 01-07-2010, 09:00 PM
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Generators are easy to service if you know EXACTLY What you are doing.

Find a farm tractor shop and have them do it, or have them recommend someone.
Most shops that don't do the work themselves will gladly direct you to someone that will do the job, and they will know who can, and more importantly who CAN NOT do the job correctly!

Brushes are just the tip of the ice burg with a mechanical generator...

You have to smooth out the commutator, that takes an armature lathe,
You have to cut between the commutator blocks since the copper wears and the resin holding them in will smear onto the commutator contacts and break contact with the brushes.

The bearings need replaced, and someone should probably 'Time' the field windings again when it's done.

Plus you are usually looking at nodular iron cases instead of steel, so that takes some specialized clean up equipment and preparation equipment to make that happen.

See, with an 'Alternator' (Alternating Current Generator) you produce in 3 phase AC,
Then a gadget called a diode rectifier separates the AC into DC Positive and DC Negative for your vehicle to use.

The ROTOR in the Alternator is the moving magnetic FIELD,
And the STATOR is the fixed windings around the outside of the rotor that produce current.


Generators are fundamentally different,

The FIELD, or MAGNETIC FIELD is on the outside, fixed in case, in the form of copper windings that produce an electromagnet,

And the ROTOR is the moving coil of wire that produces electrical current as it passes though the fixed magnetic fields.

With a DC (Direct Current) Generator,
The current is actually produced in the ARMATURE/Rotor,
And as the windings in the armature/rotor pass through the fixed magnetic field, they produce both Positive and Negative pulses...

And as the rotor turns, the brushes have to be in the correct place to collect the POSITIVE pulses,
But break contact before the NEGATIVE pulses get into the system...

How you time that little feat of engineering is to move the outside magnetic windings slightly one way or the other around the armature so you collect Positive on one brush,
Negative on the other brush, and you get a proper current flow.

Some generators have movable brush holders that will let you 'Fine Tune' the current output,
But those same movable brush holders will screw you royally if you don't get them back into the body of the generator EXACTLY correct...

Rookies don't mark the case to brush contact parts (Called 'Witness Marks', and they wind up with AC output (Which batteries HATE) and diminished current production.

Witness Mark EVERYTHING, and don't clean with anything that will remove the Witness Marks if you attempt this yourself...
Shot blasting, bead blasting or sand blasting the case to clean it (common in large shops) will remove your Witness Marks, and you have to start from scratch!

So 'Timing' the case to rotor is critical so you don't get AC production getting to the battery (which the mechanical regulators WILL NOT filter out)...

Most shops do a 'Growler' test of the armature, testing the insulation on the rotor windings.
Since this rotor actually carries a full 35 amps most of the time, you can't just use a multimeter, you have to load test each of the windings individually and make sure they are insulated and the contacts are up to the job of containing 35 amps...

When it comes to timing the case with the rotor,
I do it with a volt/ohm meter, but putting one on a test bench and using an oscilloscope is the 'Correct' way to do the job...
The 'Average Joe' doesn't have an oscilloscope, so that is pretty unrealistic for a home rebuild...

If you 'Witness Mark' The end plates, the two parts of the body/case before you take the thing apart, the brush holders, ect. Then you stand a pretty good chance of getting it back together again correctly...

And do the smoothing of the commutator, then file the resin insulating material between commutator contacts correctly, then you can usually get the thing back together correctly and make it produce,
but I still time them just to make sure they are putting out clean DC (Rippled) and putting out in the correct amperage range...

I know this is a lot to absorb, and works backwards to what a modern regulator does,

But we are talking 1900s technology here...
AC alternators didn't make the scene until the invention of reliable semiconductors in the late 60s, and they were none too reliable until the early 70s!

(Semiconductors were invented much earlier, but they didn't become reliable for common automotive use until the late 60s, just so someone doesn't decide to print the entire history of the semiconductor thinking they found a mistake)

Like I said, I can graph out the wiring diagram for you,
And if you don't get good charging after replacing and polarizing the regulator,
It's probably time for some fresh wiring and/or a Generator Rebuild!
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post #21 of 31 Old 01-08-2010, 08:39 AM Thread Starter
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wow thanks for all your help jeephammer, hopefully soemone else can use all this info too.
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post #22 of 31 Old 01-08-2010, 01:50 PM
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I did this for about 10 years when I owned a Starter/Alternator/Battery & wiring shop.

Generators are 'Old Hat' for me since I'm an old fart and I cut my teeth on old tractors on the farm.

The biggest problem with DC Generators is the Commutator, the part where the brushes ride on the armature.

Those copper contacts are large & heavy, and they are set in 45 year old insulating resin...

When you spin the generator very hard, the wedges like to fly out from the centrifugal force and then things REALLY get interesting!

Once they come loose, they wipe out the brushes, brush holders and everything else they come into contact with like a spiked ball on the end of a chain until they break off,
Then usually get wedged between the armature and field windings wiping out both sets of windings.

Believe it or not,
They still make replacements for both the armature and field windings!
You will PAY for them, but they are still available...

Like I said, what I would do is find a TRACTOR repair shop locally, walk in holding the generator and ask if they repair them.
If they do, you lucked out.

99% of the time, they WILL NOT.
In which case they will know the shop that does the best job with the best rates and most times, they are GLAD to refer you to them.
(many will give you business cards to the place!)

Do you want directions on how to test the generator independently from the regulator?
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post #23 of 31 Old 01-08-2010, 03:46 PM
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The EASIEST way to test your generator is to 'Motor' it.

take the belt loose so the pulley is free.

Take a pair of jumper cables from battery to alternator, you will need both sides hooked up to the battery.

GROUND THE CASE OF THE GENERATOR, mounting ear is usually the best place to dig in to get a good ground.

Add a smaller (14 or 12 ga. short wire) jumper wire from case ground to 'G' or 'GND' terminal.
Something you can pull off easily, you are going to remove the wire during this test.

Connect the Positive jumper cable to the 'A' or 'Arm' or 'Armature' terminal.

The generator should turn like a 'Motor
(That's why we call this a 'Motor' test)

Remove the jumper wire from case ground to 'G' or 'GND' terminal, and the generator should speed up.

If you pass this test, (and most do)
Then the generator is functioning fine and it's time to get the regulator working...



Also, you want to 'Polarize' the regulator as per instructions on the case.
to polarize the case, you are just connecting the battery (Via starter relay) to the Armature of the REGULATOR,
You simply connect on one side, then 'Brush' the other terminal with the wire. One tap is all it takes.

After you polarize the voltage regulator,
You can hook up a volt meter to the battery,

Start the engine (with belt hooked back up), run the RPM up to around 1,500 RPM and hold it there,

And SOLIDLY make contact between those two terminals again...

Voltage should climb VERY QUICKLY to around 18 to 24 volts.
You want to stop anything pas about 15 volts (remove the jumper wire from regulator) because the high voltage is hard on the battery and regulator.

Your voltage should drop back to around 14 volts if the regulator/generator is working.

If the voltage drops to below 13.5 or doesn't come up above battery voltage before you started the test, then something isn't working,
Generator, regulator, or wiring in between everything...

Mechanical regulators will 'Blast Charge' then cut out, then charge again, so make sure you observe to see if it's cycling correctly and you didn't just catch the regulator in an 'Open' cycle.

At 1,500 RPM, battery voltage should come up fairly quickly to around 14 volts, and if it gets above 14.5 volts, you need to clean/adjust the regulator.

If it's charging (battery showing more voltage than it was before testing (but not getting above 13 or 13.5 volts)
Then the regulator need servicing or replacment.

Most of the regulators will have two or three sets of breaker points.
One is HIGH VOLTAGE cut 'Out', one is HIGH CURRENT cut 'Out' (identifiable by much thicker wire in the electromagnet)
And one is LOW VOLTAGE cut 'IN'...

You can usually tell which one is welded shut or not making contact.
If they are welded shut or held open by carbon buildup, they will not appear to move at all.

If they seem to be working, but the regulator isn't working correctly,
(usually SOME voltage to the battery, but not in the 14 volt range)

That's usually either resistors (metal tabs on both ends of a white tube material with fine wire wrapped around it) located on the bottom side of the regulator,
Or it's carbon build up in the breaker points not letting full current pass through the breaker points.

Most of the mechanical regulators will have set screws that allow you to change the opening of the breaker point gap.
That's there for you to adjust after cleaning breaker points and squaring the face of the contacts up with a point file.

Point files are something that virtually NO ONE has anymore!
So you may have to substitute a piece of emery cloth for a breaker point file if you choose to try this.

By moving the adjuster you can bring the high & low voltage limits back into spec after filing/cleaning...
You WILL need an accurate volt gauge and you WILL need an insulated screw driver or Allen wrench since you can get quite a jolt while setting the points to their proper positions!

Don't forget to use some dielectric grease on the gasket under the cover before you put it back on because water getting in there is a BAD thing!

Last edited by JeepHammer; 01-08-2010 at 04:12 PM.
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post #24 of 31 Old 01-08-2010, 05:59 PM
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Wow. Amazing information here! I keep imagining an old Jeep 100 years from now that people in the future would have no idea how to repair. All that knowledge may have been lost.

Either that or the entire contents of the Internet will have been stored on everyone's imbedded communicators and they'll run across this post, feed it into a magical 3d printer and the new generator parts will appear almost instantly.
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post #25 of 31 Old 01-08-2010, 06:32 PM
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I don't know about all that.

I just know not every one knows how to work on a DC generator anymore.
Took me about two weeks of 'Tinkering' to figure out how they worked, what went where to make it do this or that.

When I was about 12 or 13 years old,
You could pick these things up for little or nothing since every farmer around here was 'Upgrading' to Alternators,
So I scooped them up and turned them into everything from wind powered to water powered to having a series of them belted to 15 horse Wisconsin gas engine to start farm equipment and heavy machinery in the winter.

It's like knowing how to wire up a Series/Parallel switch,
Since trucks, tractors and heavy equipment don't use all 6 volt batteries but have 12 or 24 volt starters and/or generators/alternators on them any more,
Virtually no one knows about Series/Parallel switches, and they darn sure don't know how to wire one!

I don't get along with people all that well,... I never did...
But I get along with 'Gears & Wires',
And electrical principals are ALWAYS the same,
Wiring doesn't lie,
And it waits PATIENTLY for you to figure the 'Issue' out,
So it's right up my alley!

Once you figure out the link between magnetism and how to strip off the extra electron on conductive materials,
(Induction: To Induce that electron movement by using a MOVING magnetic field)
The rest is easy....

All I'm doing is 'Reverse Engineering' this stuff.
I get to stand on the shoulders of true mental giants that way! (Easy way to look 'Smart'!)

It's the guys like Nicola Tesla that figured all this stuff out in the first place...
I'm just a freeloader on the backs of genius!

You can spin a coil of wire in a magnetic field (Generator) to induce an electrical current in the spinning windings,
You can spin the magnetic field inside coils of windings,
Inducing a current in the windings (Stator)... Like an alternator does...

Since the Commutator is the weak link with a generator,
You can only produce in single phase by spinning the armature...
The current you can produce is limited by how long the commutator will stay intact and how many windings you can stuff into a very limited space...

The solution to that was by spinning the (electromagnetic produced) Magnetic Field,
And putting several coils of wire on the OUTSIDE of the moving magnetic field.
Since the OUTSIDE diameter of the rotor is larger, you get more room to have more coils of wire (Alternator),
And then along came the Diode (one way polarity 'valve') to rectify the AC output into DC power and we have the modern alternator...

Truly a stroke of genius!
I didn't invent it, but I sure made a pretty good living off the guys that did!

I often use a large capacitor (electrical 'Storage' device) to smooth out the 'Ripples' in the current stream,
And I've been known to use diodes with generators to keep them from burning up the regulator if something goes wrong...

The same principal of a coil of wire (Stator) around a magnetic core is how our electronic ignition triggers work.
The 'Reluctor' passes through that core magnetic field, making it move around and INDUCES an electrical current in the stator.

Same thing for crank sensors on fuel injected vehicles,
Proximity sensors in industrial applications, ect.

The same electromagnetism principals make an ignition coil operate, Transforming 12 volts to the 20,000+ volts it takes to fire a spark plug...

Or a line transformer that 'Steps Down' the line current (usually 7,000+ volts) down to 110 volts that your home operates on...

Once you get that figured out, that it takes a MOVING magnetic field through a coil of wire to produce a current, you are off to the races on this stuff!

Some reading for the 'Geek Oriented' folks!
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post #26 of 31 Old 01-10-2010, 06:06 PM
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My 66 has done the same, need help?

Originally Posted by CJ65_JK10 View Post
so heres the scoop, since it has dropped to sub-freezing temps old red my 65 cj5 has been throwing all kinds of problems at me. it wouldnt cranks the starter would fire but wouldnt turn over the engine? so i blamed it on the cold and figured id try when it was warm, so i tried that and click, nothing. jump started it and it ran fine and drove it for about an hour back and forth across town hoping it would charge, went to autozone and had them test the battery and the battery is good, but because it wouldnt start his tester wouldnt check the alternator. so longer story shorter. he told me he believes it to be the voltage regulator. it is an f-134 engine with all original components. i doubt the volt reg is original, so im not too much worried about using any old volt reg,. but i dont want to replace the alternator with a new one if i can save the old one or buy and original "clone." any thoughts as to other fixes or advice would be greatly appreciated thanks
I saw your request and my 66 willy's has the same damn issue?? Except, I can't even get the rig jump started. There just seems to be a lack of power and the it turns real slow? I had the batteries checked and they tested fine. Any help you can provide would be much appreciated. Thanks
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post #27 of 31 Old 01-12-2010, 01:35 PM Thread Starter
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Barlow do you have a haynes manual. theres a pretty good troubleshooting guide in those for why its not starting i could look at mine but im in the middle of lake huron breaking ice. sounds like its not so much your alternator/wiring system as it is your starter. or your battery is truly good but you dont have a good connection on the battery cables. i had that problem once. everything would turn on except it wouldnt start. try tapping on the connectors on top of the battery with a hammer. NOT TOO HARD!! also check the other ends make sure that theyre not all corroded and loose. auto zone or maybe even walmart will have battery terminal cleaner. i wouldnt use steel wool because it can catch on fire. fun to do but will ruin your day. did you have the guys at auto zone or walmart or w/e test your battery? but in my experience if you cant jump it and it wont start. it would either be corroded terminals or loose terminal. but it may also be your starter... which is another story.

oh and if its a '66 its a kaiser not a willys. i wish they were willys

try that and if not then come back and im sure some one on here can help you with starter problems. unfortunately i only know how to fix what has broken on mine. haha,. so if it hasnt gone bad on mine i havent bothered to learn it yet,
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post #28 of 31 Old 01-16-2010, 06:56 PM Thread Starter
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alright so heres the news on ol red. i got the new regulator and replaced all the old wiring, got her looking good, charged the battery for a couple hours took off driving. the amp light was burning bright the volt meter was right on. and life was good. then about 15 minutes down the road the heater quit working. thinkin it was nothing but the aftermarket heater crappin the bed kept on truckin. then the radio started getting softer and softer and died. at this point i realize the battery is dead and im in trouble so i pull a u turn and then she dies. so i had a buddy come jump start me and left the cables on for about 10 minutes to juice her up a lil and made it home. so tonight i went and bought a 26 dollar alternator and all the guys at advanced auto walked me through how to hook it up so im ready to go. but then this old guy at walmart who overheard me on the phone told me a place that might be able to rebuild the generator. so im going to call them in the morning. said the guy rebuilt his alternator and starter for 12 bucks. and its worked for 5 yrs. so sounds like a little hole in the wall. my kinda place. where a 10 minute fix results in 3 hours of talkin and watchin him work.

also he mentioned calling tractor supply or ginop and seeing if they had a 12v 35amp generator. so my question is. does anyone still make a generator that will fit and be close to whats in it. because this shiny alternator is going to be hideous in my sludge covered engine compartment.
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post #29 of 31 Old 01-16-2010, 08:34 PM
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Rub your hands over the greasy suspension and engine, and then all over that nice shiny alternator - won't be so purty anymore!

With that AMP light on, it's telling you that the alternator (generator in your case) isn't putting out properly. The light usually grounds thru the voltage regulator when the system is off (or not working properly) and gets power thru the ignition switch. Once the alt/gen is putting out properly, then there is now 12v on each side of the bulb, so the bulb goes out. This may not be a good description, but best way I can think of it now. JH may be able to better explain it.

Run the alternator til the generator is back in shape, then shelf the alternator for backup...


1978 CJ5 5.0HO/T177/D300, '86 D30/D44 WT axles, 'glass body, 31x10.5 BFG A/T, TDK galv'd frame - DD and weekend toy
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post #30 of 31 Old 01-16-2010, 08:47 PM Thread Starter
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Wow I thought the amp light was a good thing. Haha. Anybody have any suggestions on the best way to install the alternator. It's a pretty common delco unit. They told me to jump the battery terminal to the field terminal to convert it to a 1 wire system then leave the pos battery cable on the starter relay and run another jumper from the batt terminal on the Alt to the starter relay and then run the stator term to a ground. Does this sound right sounds too simple to me
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