The GMC CCKW

Well I have been having an intermitant charging issue with my CCKW. For Memorial Day and doing my before operations PMCS and preping the truck for the parade I noticed the truck was not charging and was discharging when the lights were on. So I cleaned all the connections on the generator. But still no charge so I placed the battery on the charger over night to be on the safe side for the parade.
Parade day came and it was raining and when I started the truck, she was charging so concluded that with the moisture it had solved a ground issue and she charged the whole day. Cleaned all the grounds the day after and figured I had it solved. But for Saturday Dec the 6th I went to do my PMCS of the truck for Sunday as we were going to be doing a living history display at one of the local museums for Pearl Harbor Day and once again no charging...
So rechecking everything and all connections I still had no cause, I checked the generator and it was showing it was putting out a charge. So It was dark by this time and I resolved it was dirty connections inside the voltage regulator. And I would get up early and clean them up. So at 0800 was outside and everything was frozen and white with frost as we had a late night rain shower before the frost.
And spraying penetration oil on the voltage regulator screws I got all 4 out with out much issue. And when I pulled the cover off black nasty water and ice came out from inside the voltage regulator. I figure about 2 inches of water were inside looking at the water marks inside the cover, and my sealed unit was not so sealed after all.
My heart fell as I looked and everything inside was rusted and frozen solid... It was obvious the water had been in there for a very long time. So I started the truck and closed the hood and let the fan and the engine heat thaw and dry the regulator, while I waited I checked tire pressures and added air to any that were low..
After about 15 minutes everything was thawed and dry under the hood. I disconnected the battery and sprayed the whole regulator with electrical contact cleaner and cleaned all the contacts inside the regulator and made sure all were free and not seized or rusted and in about 45 minutes of cleaning, amazingly she is charging. If you could of saw how bad the regulator inside looked you would not think it possable.
So I suggest that you check your voltage regulator and make sure your "sealed" unit is truly sealed and not secretly letting water seep inside over god knows how long and letting water build up inside your voltage regulator cover like mine did.
And anyone know where can I order a new voltage regulator?

Hi Doc

Frank von Rosensteil has rebuild kits for them, he may also have gaskets
NOS versions do appear at vendor/shows now and then.
I assume you need 6volt negative ground.

Hope this helps
John

John,

Yes she is still 6 volt negative ground, I've have had no need to change over to 12 as she has been extreamly reliable the way she was made. But even thought the regulator is working but with as bad as the insides are corroded I'm sure it will just be a matter of time till she stops working for good. So I'd best get a spare.
The M20 is still there, I've done some little things to it and removed some of the welded on metal around the windows and other stuff. I've also got the winch in the crew compartment unbolted. But my shoulded surgury kept me from doing the stuff I need to do. So not alot been done as a total. But the radio system for the vehicle is complete and ready to go with all the antenneas thanks to alot of help for a good friend. So the thing I figured to be the last thing to be completed turned out to be the 1st thing done on the restoration. Go figure...
Thanks for the tip from Frank, I need to get a new catalog from him as mine is MIA. Thanks for the tip.

I am not sure what a "rebuilding kit" for a voltage regulator is, but be advised that if it includes new relays and they are not properly set up, you can do damage to the generator