charging issue
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charging issue
I have a 1997 F150 4.6 liter 4x4. It has an intermittent problem with the charging system. It will stop charging the battery (voltage dropsto12.0)then starts working again (voltage jumps to 14.3). I had the alternator bench tested and it passed all the tests. All connections seem good. Does anyone know of a problem like this with these trucks? Any advice would be appreciated.
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Make sure all the grounds are cleaned up and I had an internal wire failure at the swaged terminal of the the + battery cable on one vehicle that gave problems similar to yours. If these are not found to be a problem, then I would surmise that there is an intermitant open or short in the alternator itself. Won't always show up on the test rig.
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Joined: Jul 2005
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i have had a variety of FORD alternators, and the average life is about 150,000 miles. Yes, some will go 250,000, some have trouble at 120,000, but a good portion are severaly worn inside at 150K... If all else fails, keep that in mind.
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Charging System
I'm going through a similar situation myself. 99 XLT 4.6 2wd. 120K miles. My initial heads up came when my voltage gauge dropped significantly. Got it home just before it died. I assumed the alternator was bad. Took it off and had Autozone check it. supposedly tested "good". reinstalled it, charged the battery for about 30 minutes. Cranked it, then removed the negative battery cable. Engine did not stall, so I agree the alternator was working at that moment. Still, there had to be something wrong. I decided to replace the battery since it was six years old. After the replacement, a different problem was revealed. The charging gauge was normal, but now the charging light is on, intermittently. My next move is to replace the alternator brushes. Not many places will sell them, but I found them at Napa for about $15.00 I'll be replacing them tomorrow. I will update my progress. Hope this info helps.
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From: colbert washington
I just replaced the brushes on my alt. Its in a 98 with a 4.6 ltr v8. One brush was severly worn down the other about part way. Both internal rings had a groove in them but looked to be only about halfway worn through. My initial problem arose last summer under hard excelaration the no charge or battrey would light up. As the truck shifted down the light would go out. Its working ok now but if I have anymore problems the alt will get the heave ho and a new one will be put in. I got the brushes from Autozone. I can get you the part # if you want. Im pretty sure I have a heavy output alt as the truck is set up for trailer hauling with that package. It has close to 116,000 miles on it.
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Charging System
Thanks Vic. I'll be taking it apart today after work. Not sure what I'll find. The alternator has been replaced at some point by the previous owner so I'm not sure how many miles are on this one.
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Charging System
I installed the new brushes yesterday. As with Vic's, one brush was completely worn down. The other had a fair amount of material left. The reason, one split ring is pitted causing excessive wear. It's charging though and I hope it lasts for a year or so. At that point, I will replace it. Thanks to all for the good advice.
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follow up
The charging system worked great for one month after the alternator bench tested good, then started acting up again. This time I noticed it would charge properly when the motor was cold and for the first 10 minutes of driving, then give out, definitely pointing to something electrical. I put in a rebuilt alternator and everything has been fine since. Thanks for all the advice.
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The old Delco's with the internal regulator would have a brush wire louped under the brush and would catch it when 1/2 worn out putting the alt off line and the split ring toast from the iffy contact for a while. You could clean it up and uncatch the brush and the alternator would work some months more before smoke time again. Bowties ? LOL
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From: colbert washington
I installed the new brushes yesterday. As with Vic's, one brush was completely worn down. The other had a fair amount of material left. The reason, one split ring is pitted causing excessive wear. It's charging though and I hope it lasts for a year or so. At that point, I will replace it. Thanks to all for the good advice.
Update I doubt that repair will last you a year. I just got back from a weekend trip of about 1,000 miles. Good thing it didnt go out in the middle of the road trip. Got home last night charge light is comming on again under hard acceleration and headlights will dim down. As was previously mentioned repair would probably not last. Time for a new or rebuilt alt. The one currently in the truck will get the heavy ho as I stated before.
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