Gen1 overcharge

[Unluckyfett]

Hi,
I want to start off with thank you for all the information everyone has shared in all the threads. I know there are tons of threads about alternator problems and the stickys have made everything much easier, but I need some help understanding where I'm going wrong.

Long story sort of short:
Bought M1008, gen 2 light not lit on bulb check. Dash lights didn't work. Cleaned all dash contacts. Fixed dash lights. Did doghead starter solonoid mod, Found fault in gen 2. While rebuilding gen 2 broke case. Bought new isolated ground 27si. When installing new gen 2, tightening the nuts, the ring terminal turned and caused direct short (rookie move). Direct short let the smoke out of gen 1. Rebuilt gen1, no regulation. 32v across both batteries 17v on front battery 14.5v on rear. Rebuilt gen1 second time, same result.

Is there anything external that would cause the alternator to not regulate?

At this point I'm going to buy a second new isolated ground alternator and maybe I can eventually figure it out.

If anyone has any thoughts please feel free to tell me, at this point I'm assuming I've screwed up rebuilding it.

Thanks for all the help

 

[cucvrus]

I have worked on CUCV's over 30 years and other vehicles all my life. I have repaired many issues in the CUCV charging system. The Starter relay has nothing to do with the charging system. (just to eliminate that) I can replace every part on the truck but do not know and understand every part and it's inner workings. After years of working on any vehicles I learned that there is much more to automotive components than just replacing a few parts in them. I took a tour of an automotive electrical shop while in 1976 Vo Tech. The equipment and testing that was done to each starter, alternator and other electrical component made me a believer that I was not qualified or equipped to do rebuilding. I seen them cutting and balancing armatures and many other things. I have replaced a few contacts internally and only as a temporary fix. I have a few older tractors and they are simple but I still depend on competent specialty shops to get work done on the components. After this long winded rant I will say take it to a competent automotive electrical shop and get it checked out. I have had little issues that eluded me and $50. fixed the issue and I lived happily ever after. These trucks can be a handful if they are hacked and modified. I bought a few from local dealers that were basically basket cases. Good Luck. It is a simple system just a bit antiquated by todays standards.

 

[Tow4]

Hi,
I want to start off with thank you for all the information everyone has shared in all the threads. I know there are tons of threads about alternator problems and the stickys have made everything much easier, but I need some help understanding where I'm going wrong.

Long story sort of short:
Bought M1008, gen 2 light not lit on bulb check. Dash lights didn't work. Cleaned all dash contacts. Fixed dash lights. Did doghead starter solonoid mod, Found fault in gen 2. While rebuilding gen 2 broke case. Bought new isolated ground 27si. When installing new gen 2, tightening the nuts, the ring terminal turned and caused direct short (rookie move). Direct short let the smoke out of gen 1. Rebuilt gen1, no regulation. 32v across both batteries 17v on front battery 14.5v on rear. Rebuilt gen1 second time, same result.

Is there anything external that would cause the alternator to not regulate?

At this point I'm going to buy a second new isolated ground alternator and maybe I can eventually figure it out.

If anyone has any thoughts please feel free to tell me, at this point I'm assuming I've screwed up rebuilding it.

Thanks for all the help

No regulation is usually caused by the regulator or something in the alternator being shorted, causing the regulator to go full field. The higher the engine rpm, the higher the voltage. I've had this happen. Rebuilding the alternator solves the problem. There is a link in my signature to my alternator rebuild thread. Read it and disassemble your alternator and check the parts. Pay attention to the insulators on the regulator screws and the rectifier. An isolated ground alternator also needs a ground wire from the rectifier to the regulator. There are pictures in the thread so you should have no problem figuring it out.

I would unplug the regulator connector on the alternator that is over charging to see if it turns off first.

You can test the alternator on the truck by unpluging the regulator connector and putting a jumper from the alternator under test B+ terminal to regulator terminals #1 and 2. The B+ and B- terminals from the truck to the alternator have to be attached also.

 

[Unluckyfett]

No regulation is usually caused by the regulator or something in the alternator being shorted, causing the regulator to go full field. The higher the engine rpm, the higher the voltage. I've had this happen. Rebuilding the alternator solves the problem. There is a link in my signature to my alternator rebuild thread. Read it and disassemble your alternator and check the parts. Pay attention to the insulators on the regulator screws and the rectifier. An isolated ground alternator also needs a ground wire from the rectifier to the regulator. There are pictures in the thread so you should have no problem figuring it out.

I would unplug the regulator connector on the alternator that is over charging to see if it turns off first.

You can test the alternator on the truck by unpluging the regulator connector and putting a jumper from the alternator under test B+ terminal to regulator terminals #1 and 2. The B+ and B- terminals from the truck to the alternator have to be attached also.

Thanks, I just wanted to make sure I wasn't missing something outside the alternator. I've read the Delco manual and I feel like I have a pretty good grasp on theory of operation but for whatever reason the regulator seemed to be my problem. I ordered a new alternator just so I don't have to mess around with it anymore. I'll try rebuilding the 2 extras I have for either spares or maybe throw one in one of my jeeps.

I pulled the regulator plug with it off and started the truck, no charge until I reved it up and it stayed charging, still unregulated, until I shut it off. I also double checked the batteries and had them load tested as my direct short had drained them a fair amount. They both passed. Prior to reassembly the last time I checked continuity on all points on the regulator to ground. The only point on the regulator that had full continuity to ground was the screw that isn't isolated in civi configuration. The others were diode to ground and open lead.

I'm still unsure where I went wrong, but Im pretty sure I went wrong. I think part of my problem is the converted replacement civi case. Although in the driver side if the isolated ground isn't perfect it shouldn't matter anyway.

I followed one of the walkthroughs on this site the first time, and it was full fielding. I replaced just the regulator and I only had 11v on the b+. Third time I "switched" my converted civi case back to civi style wiring with all new components and had the same results as rebuilding as isolated ground the first time. I had 3 different rebuild kits from 3 different sellers on ebay. I'm getting the vibe that I keep making a fatal mistake, particularly with the regulator.

We'll see if the new alternator solves my problems or at least this problem

 

[Unluckyfett]

New alternator is in, gen 1 light is on. It's charging at 13.3. the alternator is too hot to touch after testing for 5 min. I'm at a loss.

 

[Tow4]

I've looked at the rebuild kits on eBay. They only have two insulated screws for the regulator/brushholder assy. In an isolated ground alternator they all have to be insulated.

The drivers side alternator doesn't have to be isolated ground. If the light is on, it shouldn't charge. Pull the plug off and see is it stops charging. The light should turn off. Under normal circumstances the the charge voltage is about 14.5. I would take the alternator and have it tested.

 

[Unluckyfett]

I've looked at the rebuild kits on eBay. They only have two insulated screws for the regulator/brushholder assy. In an isolated ground alternator they all have to be insulated.

The drivers side alternator doesn't have to be isolated ground. If the light is on, it shouldn't charge. Pull the plug off and see is it stops charging. The light should turn off. Under normal circumstances the the charge voltage is about 14.5. I would take the alternator and have it tested.

I pulled the regulator plug. Light goes out, doesn't charge. Rev it up, still doesn't charge. 12.0v on both pins of plug while running. Alternator cool to touch. plug it back in, and start the truck, b+ 13v. Light on. Within a minute it was hotter than gen 2. I took it to AutoZone to test and it failed. Either I got a bad alternator, or something external is causing them to fail instantly. I rang out the wire back to the firewall block, then to the battery and the negitive post of gen 2. Resistance is .2-.3ohm for the run. The previous owner taped up some of the wire, the insulation is gone, I retaped it for now, I plan on replacing. I have a hard time believing that 3 rebuilds and a new alt are all bad, but I can't figure out what might be wrong externally. The last rebuild I did tested ok at AutoZone and didn't regulate once it was in the truck. Part of me wants to swap gen 2 to that side and see what happens but if it kills it then I'll have 2 new dead alternators.

I guess I make a warranty claim and see what happens.

 

[Tow4]

If it's a new alternator, return it and get another. Have it tested before you leave the store.

Since the light turns off when you unplug the regulator I think the truck regulator wiring is ok. The only way to generate a lot of heat in a small amount of time is a high current short/load. Are you sure the B+ and B- wires for that alternator are correct and not damaged? You could temporarily by-pass the truck wiring and run a couple of wires directly to the battery (front for the drivers side) from the alternator B+ and B- posts. If the alternator is not isolated ground you only need the B+ wire. I told you how to turn on the regulator with a jumper above if you are not sure about the truck regulator wiring.

 

[Unluckyfett]

I think we got it figured out. New alternator in. I ran a 10ga wire directly from the b+ to the battery. At the b+ post I have 14.6v. on the battery I have 13.8v. I rechecked my wire and the insulation on fuseable link between the block on the firewall and the battery wasn't the greatest, so I cut it out to test. Hooked up the original wire less the fuseable link and I have the same result as the jumper. I know 13.8 is low on the battery but it's not fully charged after 10 or so starts. I'm getting some fuseable link from Napa tomorrow. I'm thinking the fuseable link wasn't allowing enough current to pass (even though I had normal resistance and voltage) and that was causing the alternators to fail. Is that a sound conclusion?

Thanks for all the help