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1992 Ford F-150 Alternator

Tiny
DAVID W. PADGET
  • MEMBER
  • 1992 FORD F-150
  • 6 CYL
  • 4WD
  • MANUAL
  • 150,000 MILES
I have a 92 f150 with alternator problems. I have installed 4 new ones and all but one of them would squeel at first start up after the installation. Ofcoarse the place I got the alternators from said my belt was slipping. Had it checked, belt was new, and it wasn't slipping. The one alternator that did't squeel lasted about 2 months before it went bad. Have installed 2 since, new, and both squeeled at start up. After they reach engine rpm and voltage gets up, they quit squeeling. I have taken the vehicle to a mechanic an had the charging system checked and it checked out ok. He used a self testing system machine which applied different types of loads to the charging system and was fine. So at this time I am stumpted. The last alternator I put on was bench tested to see if it was working properly before I put it on, and it tested ok. Any information would be helpful to me. Could I be getting bad alternaors?
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Sunday, July 18th, 2010 AT 12:43 PM

20 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Is the noise the same with each?
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Sunday, July 18th, 2010 AT 10:28 PM
Tiny
DAVID W. PADGET
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  • 11 POSTS
As per your question, yes it is the same noise with all of the alternators. Almost like a metalic sound.
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Tuesday, July 20th, 2010 AT 7:23 PM
Tiny
JACOBANDNICKOLAS
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I have to be honest, if the belt is new, the tensionier is good so the belt doesn't slip, I would try a different brand of alternator. If you hear a metalic sound, it seems there is a bearing problem in the alt. If you were to remove the belt and spin alt, is it smooth and quiet?
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Tuesday, July 20th, 2010 AT 11:55 PM
Tiny
DAVID W. PADGET
  • MEMBER
  • 11 POSTS
I will have to check how it feels with the belt off. One of the alternators I took back, the guy that sold it to me told me the belt was slipping and I told him it was not, so he put belt dressing on the belt and when I started the vehicle it squeeled louder every time it hit the belt dressing. One more question for you on a possibility. When I get the new alternators they take my old pully off the turnin alternator and put it on the new one. Is there a chance that they could overtighten the pully and mess up the bearings. Just a thought. Thanks will get back to you on the freeness or drag on the alternaor with the belt off.
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Wednesday, July 21st, 2010 AT 6:48 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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The bearings are not affected by tightening that bolt. However, I glad you mentioned it. Does the pulley have any glaze or anything on it? Are you sure they are making it tight enough? Is there a keyway on it?

Try this, before replacing the alt, clean the alt pulley really well with a good cleaner (something like brake cleaner would take all dirt, grease, glaze off. Just don't spray it on anything too hot or where there could be a spark. It is very flamable.

Let me know if that makes a difference.
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Wednesday, July 21st, 2010 AT 11:53 PM
Tiny
DAVID W. PADGET
  • MEMBER
  • 11 POSTS
I to the belt off of the alternater and checked to see if ther was any dragging or hard spots, it just had a sort of whosh hum sound, which may be a normal drag sound. Will try the pullly and get back. Thanks. Also can you disconnect the wires electric from the alternaror and start it and see if there is a squeel then. Have a good day.
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Thursday, July 22nd, 2010 AT 10:22 AM
Tiny
JACOBANDNICKOLAS
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You can, but one of the wires is hot directly from the battery so don't let it short out on anything. It will either cause a fire or burn a fuseable link.
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Thursday, July 22nd, 2010 AT 11:14 PM
Tiny
DAVID W. PADGET
  • MEMBER
  • 11 POSTS
I took the belt off and cleaned the pulley, looks like new, but low and behold it still squeels. I have had other people stand by when starting vehicle, and the squeel is emitting from alternator or imediate area.
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Saturday, July 24th, 2010 AT 1:53 PM
Tiny
JACOBANDNICKOLAS
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I was hoping that would fix it. If the alt does it every time, there has to be something placing one heck of a draw on the alt at start up.
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Sunday, July 25th, 2010 AT 12:06 AM
Tiny
DAVID W. PADGET
  • MEMBER
  • 11 POSTS
I disconnected the battery, took the wires loose that go into the alternator at the voltage regulator, rehooked up the battery, started the vehicle and there was no noise. Shut rig off, disconnected battery again, and put the regulator wire back in. Tried restarting the rig, and the noise is there again, until it reaches the 14.7 volt charging. So I am going to assume it has something to do with the voltage regulator section.
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Sunday, July 25th, 2010 AT 3:30 PM
Tiny
JACOBANDNICKOLAS
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That was a good idea. Now, are you able to replace the regulator on that year?
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Monday, July 26th, 2010 AT 1:14 AM
Tiny
DAVID W. PADGET
  • MEMBER
  • 11 POSTS
I have been told the voltage regulator is in the alternaor and doesnt have an external regulator
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Monday, July 26th, 2010 AT 4:46 PM
Tiny
JACOBANDNICKOLAS
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It could have an internal or external. Regardless, both are replaceable. The "internal one" is mounted to the outside of the alt housing. Here is a picture of it.


https://www.2carpros.com/forum/automotive_pictures/249084_a_5.jpg



Since the alt is new, I would say it is good, but one can never tell.
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Tuesday, July 27th, 2010 AT 12:33 AM
Tiny
DAVID W. PADGET
  • MEMBER
  • 11 POSTS
If it is the regulator on the alternator, why would this happen on 3 out of four alternators put on. What would maybe cause them to get knocked out as soon as I try and start the vehicle. I can see maybe putting a new regulator on, but just in case it does it again, what do I do then.
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Wednesday, July 28th, 2010 AT 8:14 PM
Tiny
JACOBANDNICKOLAS
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If it still happens, we need to look for a short that is putting a huge load on the alt when it first starts. Keep in mind, you may want to even try a different brand alt.
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Thursday, July 29th, 2010 AT 12:08 AM
Tiny
DAVID W. PADGET
  • MEMBER
  • 11 POSTS
I put a new alternator on today, a different brand from another auto outlet. Starteded it up and still have the squeel. Quits after it gets up to charging. Tried starting it with the lights on, ac on and just makes it squeel longer, but stops when gets to charging speed. The new alternator came with a new pully. So I have no idea as to where to look and where might a dead short may be coming from. Any ideas.
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Saturday, July 31st, 2010 AT 7:08 PM
Tiny
DAVID W. PADGET
  • MEMBER
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I sent a reply back to you about putting on a new alternator and have the same thing happen when I started it up, with a differernt brand alternator. It only does it now when I first start it up, but when it warms up does it less often. I checked all the wiring that goes to the alternator to see if there is a short between the wires somewhere and found nothing. So I there is a dead short where would I start looking now.
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Saturday, August 7th, 2010 AT 10:41 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Start at the PCM. Make sure the wiring harness is tight and not corroded. Also, check wiring along the firewall to see if there is any evidence of a short. It has been a while since I spoke with you. Are you absolutely sure the belt has enough tension?
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Sunday, August 8th, 2010 AT 1:01 AM
Tiny
DAVID W. PADGET
  • MEMBER
  • 11 POSTS
After your last message I rechecked the belt tentioner and I replaced it. I have no squeel at this time. I had checked it before and everything still squeeled when you put a little more tention on the belt. But guess it is like a christmas list, you have to check twice. So thank you for all your help and input. I do believe some of the alternators I did have were bad. Hope you have a great week and thank you again
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Monday, August 9th, 2010 AT 3:33 PM
Tiny
JACOBANDNICKOLAS
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Wow, I am really glad you got this fixed. If it was an electrical short, we would have both gone crazy tracking it down.

Take care, and I happy to help. If you have questions in the future, let us know.

Joe
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Tuesday, August 10th, 2010 AT 10:10 PM

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