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Tue Nov 10, 2009 3:11 pm

My generator is not giving a higher reading no matter what the rpm. So, now I would like to see if it is the brushes and have read that you need to try and push down on them to make a better contact possibly. Should I be using my fingers to do this, and how much pressure does it take to usually make a difference?

Also, the brush is what I can see peeking through the opening at the top of the generator with the flat surface rubbing the notched wheel right?

Tue Nov 10, 2009 3:29 pm

The brushes are not really adjustable. If the brushes are worn to the top of their holders, then it is time to replace them.

More often the culprit is the regulator, not the brushes.

Tue Nov 10, 2009 3:30 pm

I would use a screwdriver to push on them. I don't like the idea of my fingers being that close to moving parts. What is the voltage you're getting?

Tue Nov 10, 2009 3:35 pm

i currently and testing on the battery terminals with my volt meter and getting 12.3 volts give or take points. When revved up there is no difference. I want to test the generator and read to connect a jumper from DF on the generator to the generator frame, then run the engine and measure the voltage from ground to D+ on the generator.

Could some one translate this into English for me please. Is the jumper just some wiring? If so what gauge wire? And the generator frame is what? Last, to measure the voltage from ground to D+ on the generator means take the volt meter and put red on the D+ terminal and ground the black somewhere?

Help.. please..

Tue Nov 10, 2009 3:52 pm

Start the car and touch one probe of a digital multi-meter set at 20volts to D+ and the other to the body of the generator. If it reads zero, you have a generator problem. If it reads 12 volts or higher, then you have a bad electrical component elsewhere along the wires to the battery.

Tue Nov 10, 2009 3:57 pm

lactose7 wrote: Start the car and touch one probe of a digital multi-meter set at 20volts to D+ and the other to the body of the generator. If it reads zero, you have a generator problem. If it reads 12 volts or higher, then you have a bad electrical component elsewhere along the wires to the battery.

With no modification to the wiring I started the car and put the positive side of the voltmeter on the D+ terminal and the negative touching the top of the body of the generator and it was giving me a read of 0.35.
this means...?

Tue Nov 10, 2009 4:20 pm

Have you checked all of the connections on the regulator under the back seat to make sure none of them are loose or corroded?

Does the generator warning light on the dash come on while the car is running? If so, does it dim when you rev the engine?

Tue Nov 10, 2009 4:25 pm

look at this step by step procedure on replacing the brushes if that is your problem and not just a loose connection.

http://www.reluctantmechanic.com/step-by-step/change_generator_brushes.php[/url]

Tue Nov 10, 2009 4:31 pm

Try Speedy Jim's page on Generator testing:

http://www.nls.net/mp/volks/htm/gen.htm

And here's a picture of one of the brushes, this one is hardly worn, it's way above the top of the holder:

Tue Nov 10, 2009 4:48 pm

i pulled the brush and its only about a one half inch in length. I'm going to bring some sand paper to the commutator to shine things up and replace the brush when I get a new one.

I have been looking at Speedy Jim's genertaor page and it brought up my previous question about the 'jumpers'. Is he talking about wire? if so what gauge wire? Can I use the wires that are there already. I'm having trouble trying to grasp the idea.

Tue Nov 10, 2009 5:02 pm

andrewsanteiro wrote: I have been looking at Speedy Jim's genertaor page and it brought up my previous question about the 'jumpers'. Is he talking about wire?

Yes. A "jumper" is something that electrically connects two things. In this case, it will be a jumper wire that connects the DF terminal to the body of the generator; usually the ground screw is a convenient place to do this.

Quote: if so what gauge wire?
It can be pretty skinny. It's not carrying a lot of current, and you ONLY want to do the generator test for a few seconds anyway.

Quote: Can I use the wires that are there already. I'm having trouble trying to grasp the idea.
So I think what you're trying to do is figure out if the problem with your charging system is with the generator itself or the regulator, yes? If your brushes aren't making contact, then it's the generator. However, to answer your question...

Engine off. Disconnect all three wires from the harness from the generator. That's a brown wire with a loop that's held on to the generator body with a screw, the DF wire (I think the wire is green) and then the big fat wire that goes to D+. Now, connect the DF terminal to the ground screw with a wire that will stay there. Now, get your voltmeter set up (on volts, with scale on 200). Start the car, touch the black probe to the generator body and the red to the D+ terminal (watch the belt), take the reading, then right away go back around and turn the engine off. This reading should be at least 10V, maybe 12V or more. If you have someone rev the engine while you're reading the voltmeter, it should go way up, to like 30V. Remove the jumper wire and re-connect the wiring as normal.

Tue Nov 10, 2009 5:06 pm

Yeah, he means a jumper wire. You don't really need heavy gauge wire, it's just a brief connection. If I need a piece of wire, I just dig into my box o'wires and pull something out. 16 or 18 gauge should be OK.

And yes, you can disconnect the wires at the regulator and use those to make the connections. For polarizing, I always take the fan belt off so I can see the generator spin, as polarizing also turns it into a motor and it spins along pretty well. I like to see it spin the correct way, (I've seen it go the wrong way before, or just sit there and sort of wobble undecided - in both cases I manuall start spinning it the right way and then it takes over and goes from there)

-Andy

Tue Nov 10, 2009 5:37 pm

gevmage wrote: Now, connect the DF terminal to the ground screw with a wire that will stay there. Now, get your voltmeter set up (on volts, with scale on 200). Start the car, touch the black probe to the generator body and the red to the D+ terminal (watch the belt), take the reading, then right away go back around and turn the engine off. This reading should be at least 10V, maybe 12V or more. If you have someone rev the engine while you're reading the voltmeter, it should go way up, to like 30V. Remove the jumper wire and re-connect the wiring as normal.

OK, I ran this test and pulled about 23+ volts with a quick pull on the throttle at the carb. It was all over the place from 0 volts to 23+. I'm sure it would of produced more volts had I revved it higher and longer but didn't think it was necessary.

Is this telling me my regulator has issues or what? Ill polarize it now to maybe eliminate another case. (my neighbors hate when I work on my car at night but it doesn't matter b/c they cant speak enough English to tell me to shut up. let them stare! its only 7:30 anyway, give me a break)

Tue Nov 10, 2009 5:39 pm

What kind of regulator is it - the old points-style or the new replacement solid-state style? I've had pretty good luck with the new style, much more reliable and better voltage regulation than the old.
-Andy

Tue Nov 10, 2009 5:39 pm

an old bosch. I would be quick to replace it because it is cheap but I don't want to be another one of the people I see on here stating they thought this replaced it thought this replaced it and have a brand new electrical system with the same problem.

polarize it?

keep the suggestions coming. thank you

Tue Nov 10, 2009 5:49 pm

Ah, well you said you were reading Speedy Jim's page, it talks about polarizing on it. Yours is probably good though, what with the numbers you go with the full-output test.

-Andy

Tue Nov 10, 2009 5:53 pm

I see. Can it do any harm to polarize it anyway?

Reason I felt I shuold was that the engine sat for over a year and Speed Jim's site said that some generators need it after sitting.

Tue Nov 10, 2009 6:00 pm

andrewsanteiro wrote: an old bosch. I would be quick to replace it because it is cheap but I don't want to be another one of the people I see on here stating they thought this replaced it thought this replaced it and have a brand new electrical system with the same problem.

If the generator produces voltage when shorted, but doesn't when hooked up to the regulator, then the regulator is bad.

Oh, the bouncing around of the voltage may indicate your problems with your brushes. You still need to get those right.

Quote:
polarize it?

No. If it's producing voltage it's as polarized as it needs to be.

Tue Nov 10, 2009 6:07 pm

OK. i had the belt off and polarized it anyway before reading that. No change obviously though. I did however notice the volts dropping at higher rpm. Also an indication of missing by the brushes i'm sure. at least this will be a cheap fix, i hope.

How do you get at the screw for the bottom brush?

Tue Nov 10, 2009 7:37 pm

Since I have concluded that my regulator is shot, what is the next step?
Rebuild the regulator, buy a rebuilt one, new one, new style solid state I think it is?

Also, is there a trick to getting the screw out of the bottom brush without removing the generator?