1973 Ford 4000 Voltage Regulator Issue

[deere5105]

We noticed recently that the battery light on the dash started coming on periodically. After doing some reading we came across a recommended test for the regulator. The test stated that peak operating voltage when running should not exceed 14.5V. Using a volt meter I measured approximately 12.8V across the positive and negative posts with the ignition off. With throttle set with engine RPM’s at 1800 the voltage climbed as high as 16.5V before I shut the tractor down.

If recommended test for regulator is correct then it seems obvious to me that we have a faulty regulator. I know there are still a lot of old Ford tractors out there and a lot of knowledgeable operators. Am I missing anything?

 

[deere5105]

Picked up new regulator and seem to be getting the same voltage readings as with the original regulator. Battery light seems to be going off now when RPM’s at operating speed. Was sporadic off and on with original. Time will tell if new one is any different.

 

[Richard001]

You have some crusty looking grounds near the regulator. Did you clean them up ?

Also did you clean up the connectors that plug into the regulator?

 

[Smokeydog]

My old Ford shop manuals showed how to adjust the voltage on generator voltage regulators. As contacts wore they required adjustments. Had slots where a flat screwdriver could gently pry.
Worn brushes another cause.
Poor or dirty connections increase resistance and lower voltage.

 

[TractorTech]

Picked up new regulator and seem to be getting the same voltage readings as with the original regulator. Battery light seems to be going off now when RPM’s at operating speed. Was sporadic off and on with original. Time will tell if new one is any different.

Can assume that the battery is in good shape and there are no other loads on the battery?

 

[rScotty]

If I saw those readings taken both static and running my first thought would be that the battery is good. Now I need to check that I am not reading AC when I measure running. If that 16.5 is DC - as it should be - then the next thought is one of 3 things:
Either there is a faulty charge light relay in the voltage regulator.
Or there is a faulty corroded ground connection somewhere - probably battery to frame, but maybe VR to frame.
Thirdly, it is possible that voltage can be fine or a little high and there still not be much amperage passing into the charge circuit. So I'm hoping there is a dash ammeter and it is showing positive charge.

If so, then 16.5 v isn't high enough to harm the battery if it is in good shape. I've seen vrs not regulate until they hit 18 volts. So I'm back to poor grounds or the old VR regulator has a bad relay that turns on the dash light.
At this point I'd keep the new VR and go after the frame grounds.
luck,
rScotty

 

[deere5105]

Appreciate the feedback.

I am not close to the tractor right now. I understand today starting out battery showed around 12.8 not running. At 1800 RPM showing around 16.5. After hours of bush hogging light came on. Little later when back around volt meter with charge light on and tractor running meter showed 12.4. That tells me at that time it wasn’t charging.

I believe there is both a regulator and a generator and the generator handles the charging. I believe the other light, oil pressure, also came on and began to flicker at idle.

Any of this point to anything or still possibly a ground connection issue?

 

[rScotty]

Appreciate the feedback.

I am not close to the tractor right now. I understand today starting out battery showed around 12.8 not running. At 1800 RPM showing around 16.5. After hours of bush hogging light came on. Little later when back around volt meter with charge light on and tractor running meter showed 12.4. That tells me at that time it wasn’t charging.

I believe there is both a regulator and a generator and the generator handles the charging. I believe the other light, oil pressure, also came on and began to flicker at idle.

Any of this point to anything or still possibly a ground connection issue?

OK. Well, that's new info you and yes it does change things. Glad you were able to get that measurement. 12.4 volts tells us that the battery is probably good and that it hasn't been getting the charge it was expecting. The fact that it happened after some use and heat is good info - but I'm not sure quite what to do with it until we have a bit more information.

There are two possible culprits that are real heat sensitive and both are in the generator or alternator (which one do you have?) they are NOT in the Voltage Regulator. I'm going there because what you are describing makes me think generator/alternator instead of voltage regulator.

If your old Ford has a generator, then heat after a few hours causes the pick up brushes in the generator to begin to bounce on the commutator which results in a lower voltage with an AC component. That type electricity won't charge the battery.

If your old Ford has an alternator, same problem, but in an alternator it is likely that heat affects the diode plate and causes a diode to pass current both ways.That also lets an AC signal through instead of converting it to DC. The battery cannot use AC for charging.

Both of these are relatively easy fixes if you want to keep the tractor near stock. This is when I'd take the generator or alternator down to the auto electric shop for a test and a rebuild. Rebuild your good old one. It is far better to rebuild the old one than than to buy some cheap chinese rebuilt one.

However, a workable alternative is to just scrap the old generator and voltage regulator both and replace them with any one of a dozen new one-wire combination alternator with VR built in. You simply choose one that will bolt up to your esisting mount and drive with your existing fan belt. Size it roughly the same. The single output wire goes to your battery. And you are done.

Ive heard that Datsun and Toyota single wire one-wire alternators are good ones and inexpensive. Sorry I don't have a part number. Maybe someone else has done this to their Ford.

Or just rebuild the old one. It has experience..... Oh, on the grounding. Probably not the problem, but anyone with good sense stays on top on grounding issues. They are always the number 1 culprit.
luck,
rScotty

 

[deere5105]

This tractor has a generator. We have a good local starter/alternator repair shop. Thanks for the feedback!

 

[rScotty]

This tractor has a generator. We have a good local starter/alternator repair shop. Thanks for the feedback!

You are lucky to have a good shop like that. We had one here, but our local guy retired about 5 years ago and nobody younger is interested in doing repair work. His was a one-man shop for the last 40 years.

Industry is getting away from designing things to be repairable, and that means the era of home mechanics is drawing to a close. My nephews don't even have hand tools. Well, one does but his parents discourage him.
I do see some guys - mostly old guys - doing hobby rebuilds on vintage stuff. That's encouraging, maybe the old skills won't completely die out.

rScotty

 

[deere5105]

Generator removed and tested today. Tested good.

Regulator replaced and getting same results.

Talking with a guy that works on equipment for a living to see if he can take a look at it. Appreciate all the feedback.

 

[rScotty]

Generator removed and tested today. Tested good.

Regulator replaced and getting same results.

Talking with a guy that works on equipment for a living to see if he can take a look at it. Appreciate all the feedback.

I expected it would test good in a short term test. I think you did too, since you did say in early messagesthat it took hours of bushhogging before the red light on the dash began to flash. And we know that the tests you did also show that all is charging good initially. So we know it is good until it runs for awhile.

What does the guy charge for going through a generator and doing a rebuild? If you do that and have replaced the regulator there's nothing else in the system - except for the battery & ground connections, and you checked those.

I once had a ground wire that had corroded apart inside the insulation! The connection to the battery was good and so was the frame ground lug. But as I was checking things, I reaized that the heavy ground wire from the battery negative to the frame had a weird floppy spot in the middle. Apparently acid or fumes from the battery had vibrated up the wire and stayed inside the insulation until it came to a bend, and there it ate the copper apart inside the insulation sleeve. From outside, all looked fine.
And everytime I worked on it I must have moved that wire just enough so that it worked again for awhile.

That's the last time I bought a wet cell battery. It took me a year to find that problem.
rScotty

 

[David_Kb7uns]

10si

 

[rScotty]

10si

David, I'm thinking that never has a message so short contained so much information. Thank you for that.
Let me add the words: "3 wire"

and a link:

Catalog

www.madelectrical.com

and the comment that the article above should be required reading for anyone suspecting alternator or generator problems. It details a simple inexpensive solution to charging any tractor, car, or truck.
rScotty

 

[deere5105]

Thank you for clearing that up and the link. Will read the link soon.

As an update, the charge light seems to now be staying on versus being intermittent before. Volt meter readings verify that with light on no charging taking place. Will have to decide which route to go to correct issue.

 

[rScotty]

Thank you for clearing that up and the link. Will read the link soon.

As an update, the charge light seems to now be staying on versus being intermittent before. Volt meter readings verify that with light on no charging taking place. Will have to decide which route to go to correct issue.

So just to summarize, check if I have the facts right on the 73 Ford 4000

1. The charge light comes on after running for awhile. Periodically goes off or comes on.

2. Not running, but stopped when charge light was mostly off, then the resting battery measures 12.8 volts.
3. Not running, but stopped when the charge light had been on for awhile, resting battery is 12.4 volts.

4. When running, and charge light is off, you measure as high as 16.5 volts at the battery
5. When running, and charge light is on, you only measure 12.4 volts at the battery

5. All of this remained the same when a new voltage regulator was put in.

6. Took generator to a shop where it tested good.

7. There aren't any electrical problems other than the charge light coming on periodically - and that voltmeter readins seem to indicate that when the charge light is on the system is not charging. Tractor starter seems OK.

8. You are concerned that the charge light and voltmeter indicate that something is periodically failing in the charging system and want to fix it before it doesn't charge at all.

Is all that right? Did I miss anything?
rScotty

 

[deere5105]

So just to summarize, check if I have the facts right on the 73 Ford 4000

1. The charge light comes on after running for awhile. Periodically goes off or comes on.

2. Not running, but stopped when charge light was mostly off, then the resting battery measures 12.8 volts.
3. Not running, but stopped when the charge light had been on for awhile, resting battery is 12.4 volts.

4. When running, and charge light is off, you measure as high as 16.5 volts at the battery
5. When running, and charge light is on, you only measure 12.4 volts at the battery

5. All of this remained the same when a new voltage regulator was put in.

6. Took generator to a shop where it tested good.

7. There aren't any electrical problems other than the charge light coming on periodically - and that voltmeter readins seem to indicate that when the charge light is on the system is not charging. Tractor starter seems OK.

8. You are concerned that the charge light and voltmeter indicate that something is periodically failing in the charging system and want to fix it before it doesn't charge at all.

Is all that right? Did I miss anything?
rScotty

VERY good summation! This is actually my dads tractor and I have been trying to help him with it. I understand he put it on a trailer and is taking it to a different starter/alternator shop to be tested this morning.

My synopsis is the generator is failing.

 

[David_Kb7uns]

Have an old MF35, previous owner took off the generator and put a 10si on the side with an oil pressure operated switch for exciting you may also do the key swifch or the diode with lamp to accomplish the exciting, only bad thing with the cheaper Delcos is the dust in the brushes and electronics in the back of the alternator. Live in western Oregon and literally any old piece of logging equipment has an old Delco Remy internally regulated alternator on it.

 

[deere5105]

New shop went over everything and replaced both the regulator and the generator. Said is good to go. Curious to put volt meter on it to see what the numbers are now. Also curious about regulator as the one on the tractor was new. Wondering if new one tested bad or just got replaced.

Appreciate the feedback and input.

 

[rScotty]

New shop went over everything and replaced both the regulator and the generator. Said is good to go. Curious to put volt meter on it to see what the numbers are now. Also curious about regulator as the one on the tractor was new. Wondering if new one tested bad or just got replaced.

Appreciate the feedback and input.

The VR may have been just bad from the start. Or maybe it was polarized incorrectly when you put it in.
Voltage regulators are odd little beasts, A balance of mechanical spring tension versus electrically-generated magnetic force ends up with an old style voltage regulator. Which is a device which can literally be rebuilt at the kitchen table - or built from scratch in a home workshop. And not surprisingly, manufacturing them relies on some some care and craftsmanship winding coils and setting spring rates. That attention to detailed craftsmaship is going to be more and more unlikely as the demand for that old style voltage regulator diminishes.

Demand diminishes because voltage regulation devices for the past 40 or 50 years has been switching over to using semiconductor voltage regulation circuits. It is much simpler to consistently make a reiliable semiconductor voltage regulator - that's what all the modern alternators have built into the alternator. Of course that level of simplicity can only happen after technology has advanced to the point where semiconductors even exist. .... which takes a whole industrial base itself.

Be interesting to see what your voltmeter shows when you get a chance.

rScotty