I just finished replacing the brushes on my alternator since I was having troubles with my truck not starting. I even followed the write up on the maitenance section of this site to replace them. I got everything put back together, put in a new battery (just to rule it out as the problem) and it still wont start. I jumped it w/my other truck and it started fine but once I remove the jumper cables the truck runs for a few seconds and then dies. The battery and e-brake lights still come on. I'm thinkin the alternator is just blown but I'm not sure. Any help would be appreciated as I am a little frustrated. <img src="/forums/images/graemlins/angry.gif" alt="" />

Could be the alternator's regulator that's gone bad. With a new battery, you should be able to run on the charge for awhile, though.

Did you clean the cable ends really well? Sounds stupid, but you don't have enough power to run the truck, which doesn't take much. A new battery should take you for a while, even without an alternator. With jumper cables on it, it worked, but they grab the OUTSIDE of that clamp.

Another thing is if you put the jumper cable ground onto the chassis, it could be your ground wire that isn't kosher.

Both cables and clamps are clean. I was shocked too at the fact that the truck won't run under its own power. I'll try grounding the neg cable on the body. I'm just out of ideas.

It's along shot, but check your fusible link. If it popped, the alternator won't charge.

Failing that, have your alternator bench tested. That way you can rule it in or rule it out as the cause. If something's wrong, it's easy to fix. Every part in there is replacable.

You cant trust cables by looking at them. Cables can and will corrode on the inside. I think the truck needs 2 bateries to get enough current to run the truck because the cables are so corroded. That would make sense to me why it would run with 2 batteries and not 1. Cables are pretty cheap and it cant hurt to replace them.

Easy test.... Take those jumpers and use em as stand-in battery cables. One at a time.

OK....I took my alternator to Autozone to have them do a bench test. They informed me that my alternator had a bad 'diode'. Not quite sure what that is or where it is in the alternator, but if its replacable I would rather go that route. I really dont have the money for a new or rebuilt one right now. Plus I need my truck running ASAP. Thank for all the help so far, its been great. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Have you read Bill Morgan's alternator upgrade article?

NOPE! Sure havent....but Im gonna! Can ya tell the boss is in Las Vegas this week? LOL Builders convention.

But I do have a question here...if one of the diodes went bad, then wouldnt he have had a parasitic drain of the battery such as I did with the 4Runner last week? He gets his tested and they tell him a diode dieded. Mine goes Fubar and y'all tell me its a Diode that dieded too...interesting. Conspiracy? who knows...maybe he should take it to another place for testing. If its still doing some of its functions wouldnt better guess be the IC regulator is jacked? Just wondering man...
~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />