Electrical: Amp gauge question

[CodyC]

Hello my fellow forum members. I have a 62' lark that runs like a champ but lately when I've been driving for a while the amp meter will drop all the way to the negative and then not move and my amp light will come on. The car will still be running fine even when I come to a stop and after a while the amp meter will start reading normally again.
I don't know too much about how the generator works but I figure this is an issue with the dash gauges and not the generator itself right?
Thanks in advance! I sure have learned a lot from these forums.
-Cody

[41 Frank]

Is the fan belt tight?

[CodyC]

The Fan belt is pretty loose among being old and cracked. I am planning on replacing it soon. Could that be causing it?

[studegary]

Welcome!

Start by replacing the belt with a new one.

This reminds me of a co-worker that spent a lot of money on a new battery, alternator, regulator and cables (one at a time) and still had a problem maintaining a charge. I took the car, bought and installed a new belt and gave him the car back - fixed. I never told him how I fixed the car. Of course, I didn't charge him either (as others had done).

[StudeRich]

If the new BELT does not completly fix the discharging, it is most likely sticking points in the Voltage Regulator, meaning a replacement is in order.

[CodyC]

Nice Gary!
Thanks guys I'll replace it and see what happens. And I'll take a look at the voltage regulator as well.

[Chucks Stude]

Also, check the brushes in the back of the generator. The brush holders get hot, and the brushes loose contact with the commutator, and you get an intermitant gauge. Just a thought.

[CodyC]

Ok will do. If they are getting too hot would there be a way to fix it or would it the generator need to be replaced?

[studerodder]

i have worked on cars that were down for long periods and found that rust on pulleys will cause this. glass beading fixes it nicely.

[studegary]

i have worked on cars that were down for long periods and found that rust on pulleys will cause this. glass beading fixes it nicely.

I was going to say to clean the pulleys before installing a new belt, but I thought that this would be obvious, but maybe not.

[CodyC]

Update!
So I bought and installed a new belt but my ammeter was still shooting to discharge at high rpms. After a day or two it would no longer go to charge at all. The battery died of course so I opened the VR and had a look at it and it smelled pretty bad so I bought and installed a new one and polarized it and still no change to ammeter. So I figure it must be the generator. I've taken it out and am having a look at it but I'm not quite sure of what to be looking for with the contacts in the back. Any thoughts?

[Tom Bredehoft]

Take your generator and your new regulator to a well established Auto Electric shop. They will want both, and when you get them back they probably will be better than new.

[Corvanti]

Take your generator and your new regulator to a well established Auto Electric shop. They will want both, and when you get them back they probably will be better than new.

ditto that!!!

[CodyC]

Alright it looks like that's what I'll have to do ; ;

[warrlaw1]

Cody, how new is your battery? A bad cell can cause lots of disruption, too. I'm running 6V and the battery is not a sealed unit. If the electrolyte gets low in one cell it can short or burn out a good generator. Good luck.