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The fix for my endless alternator failure's

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Old Jul 7, 2010 | 08:35 AM
  #81  
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Originally Posted by The Alchemist
Can someone please clarify the differences in the modifications to the mounting hardware? I'm just not seeing it.

Thanks.
Originally Posted by Ryanmgaspard
The stock alternator uses two brackets. One bracket has three bolts that go through the alternator into the block. This bracket also has a pulley on it for the serpentine belt. The second bracket is behind the stock alternator. It's a "L" shapped metal bracket with two bolts, one goes to the block and one goes to the back of the alternator. I'm assuming it's some kind of anti vibration bracket. If you switch over to the truck alternator it will mount directly into the 3 bolt bracket but is too big to utilize the rear bracket, "L" shaped one. So, install the truck alternator on the bracket with the pulley and leave the rear support bracket off. There's no cutting or anything involved. It's not really a mod, you just don't put the rear bracket back on. The bigger alternator also doesn't whine like my stock one did and it has more miles on it.

On a different note, this bigger alternator will also work on 98+ S10's (I believe). I will try it out this weekend and see. Also, I will see if it fits on a 2003 Mustang V6 (wife's car). We went through 4 "Ford" alternators and still have the rpm drop and alternator idiot light occasionally not to mention the power steering and alternator whine. Same goes for my truck.

Yup its a bracket that butts up against the back of the stock F body alternator, there is a bolt on the back side of the stock F body alternator, it goes through that bracket into the alternaotor.

There is one 15mm headed bolt that retains that bracket to the engine block, once you get the alternator out you can get right to that bolt.

So just take out the bolt and put the bracket and bolt somewhere. The truck alternator does not have a bolt hole to use that bolt if you even wanted too.
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Old Jul 7, 2010 | 05:03 PM
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Old Jul 7, 2010 | 05:04 PM
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Old Jul 7, 2010 | 05:06 PM
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the f bod bracket uses 3 bolts......all 3 go to the block.....only 2 go thru the alt
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Old Jul 7, 2010 | 05:08 PM
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Old Jul 7, 2010 | 05:09 PM
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this bolt hole is where the bracket bolts up....its only a 13mm bolt on the alt
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Old Jul 14, 2010 | 08:44 AM
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Originally Posted by crainholio
The shop is upgrading mine to an Israeli-made rectifier with 70-Amp diodes. It won't increase the output of the alt, but will increase the tolerance to output load at rated max. So if the alt is working hard recharging a low battery, or running at 5K+ RPM for long periods of time, the rectifier can take the current the alt is producing with a bigger safety margin.
UPDATE: I got the alternator back from the shop, the new rectifier is definitely fitted with larger diameter diodes than the Chinese unit. I installed the alt and put ~50 miles on it last weekend, charging is the usual 14.6VDC immediately after cold startup and stabilizes at 13.5VDC at hot idle.

Loading it with high beam headlights and both fans at idle brings it to 13.3VDC, at 800rpm idle and running an ATI 10% underdrive pulley. Increasing the idle speed to 1000rpm had no effect on voltage.

I got a track day for this Friday at NJMP Lightning circuit...1.9 miles of road course. The Delco new alt is in my track box just in case. Will report back with results!
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Old Jul 14, 2010 | 08:57 AM
  #88  
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I did the install of the 15263859 alternator. Couldn't be eaiser. Installing a bigger (4 gauge) cable to the battery was more work. Even the F Body plug was correct.

Now, in drive with all the lights and the AC on and with both radiator fans running, the dash volt gauge reads 13 volts. Prior to the swap, it dropped towards 12 volts.

Definatly a worthwhile upgrade and worth the cost and effort.

One more thing scratched off the list!
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Old Jul 14, 2010 | 09:41 AM
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I might have to do this while the front of the motor is torn apart doing a head/cam swap.
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Old Jul 15, 2010 | 09:48 AM
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FYI for those of you who have had problems with parts stores telling you your alternator tests fine.... I have been there before on 2 occasions with a parts store alternator that was internmittently failing. I was not going to wait to be stranded so I tried to have it replaced.

They tested it and it tested fine. I told the guy it was intermittent when I first handed it to him so I insisted he keep testing it because it would fail. It took 5 times and it finally failed. He said "Strange, I have never seen that before" I asked him if he had ever tested an alternator more than the first quick run and he admitted no. On both occasions it took multiple test to make it fail, but they replaced it. Just be persistent.

I know I will be doing this swap on the Camaro when the factory alternator dies which I am sure is only a matter of time. I am sick of the voltage dropping when things are turned on so I may go ahead and start finding the replacement. Excellent tech thread.
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Old Jul 15, 2010 | 05:48 PM
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my stock alt still works......any body need 1......cheap......
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Old Jul 16, 2010 | 08:04 PM
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Originally Posted by crainholio
I got a track day for this Friday at NJMP Lightning circuit...1.9 miles of road course. The Delco new alt is in my track box just in case. Will report back with results!
UPDATE: the new rectifier held up fine! 5 30-minute sessions in sweltering 94+F heat at NJMP Lightning road course, lots of time at 5K rpm and up, never even touched the 13V mark on the gauge.

There's something to be said for having your alternator reworked by a pro.
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Old Jul 19, 2010 | 08:30 PM
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Well I just bought one off Fleabay for $57 shipped. All the local junkyards wanted at least $100, so I said screw it. My stock one is squealing like a procharger thanks to my power steering pump constantly boiling over and leaking on the alternator. I need to put a cooler on the power steering pump to try and save this next one.
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Old Jul 24, 2010 | 10:36 AM
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So the alternator came yesterday, bolted it up this morning but was an idiot and forgot to disconnect the battery before unbolting the cable off the back of the alterator. It sparked, I felt stupid and should know better, but disconnected the battery, finished removing the stock alternator, then bolted up the one I bought.

Here it is: http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWNX%3AIT

I notice the back is a little different, and the harness that was still atatched to it had two wires coming out of the 4-wire harness, but still installed it. It bolted up fine, got the belt back on, the power wire bolted back up, plugged in the exciter wire, and recconected the battery. Go and start it, and the battery gauge stayed in the red, nothing. Check the battery while the car is running with a voltmeter and it's reading 11.88 volts, so I'm not charging.

I checked the fuses, and I can't find anything popped. Am I missing something? I'd hate to remove it, go get it checked to find out it's something simple. I'm inside cooling off because I'm pissed. Any help is appreciated.
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Old Jul 24, 2010 | 10:46 AM
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I'm wondering if when you shorted the power cable to ground if you somehow popped it. With the engine off, do you read battery voltage to ground at the stud on the rear of the alternator? If yes, put the old one back in and see if it still works.

Assuming you purchased the correct alternator, which it appears you did, this should be a plug and play job.
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Old Jul 24, 2010 | 11:44 AM
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Originally Posted by Paul Bell
I'm wondering if when you shorted the power cable to ground if you somehow popped it. With the engine off, do you read battery voltage to ground at the stud on the rear of the alternator? If yes, put the old one back in and see if it still works.

Assuming you purchased the correct alternator, which it appears you did, this should be a plug and play job.
With engine off, I'm getting 12.25 volts at the alternator wire, so it's a solid connection to the battery, and if there were a fuse in that line, it's fine since I'm completing the circuit back to the battery.

I agree it should be plug and play, but I always figure out a way to complicate things. I checked the voltage at the exciter wire, and I"m getting 10 volts with the key on/engine off, and 12 volts with the key on/engine on, so the exciter wire is working.

I guess I can install the old one and see what happens.
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Old Jul 24, 2010 | 12:13 PM
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Got the stock one back in, and started it up and all is fine. At this point, I contacted the ebay seller and am requesting an exchange and they pay for shipping of the bad one back to them. I'll give them one more chance and then I'll request a refund.
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Old Jul 25, 2010 | 09:59 AM
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So you're gonna be an expert at changing alternators!

Question (far all): When I did mine, I also replaced the AC compressor. I yanked out the sway bar as it seemed to be in the way of both items. Can the alternator be replaced with the sway bar in place?
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Old Jul 25, 2010 | 12:18 PM
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And I thought I was the only person with alternator trouble lol. I'm still using the factory style, remanufactured alternator and it's not charging. All of my grounds look fine and I replaced the exciter wire (or whatever the hell it's called) pigtail, I went and had the brand new (reman) alternator checked and it was bad. I got another alternator and it still isn't charging so I went and had it tested and it's good. Needless to say I can swap the alternator in like 5 minutes now haha. I'm freaking lost guys!

I figured I'd ask here instead of starting a new thread since ya'll seem like the alternator experts. Why in the hell are my alternators not charging? I'm about to go buy a voltmeter and start testing every freaking wire I see.

Oh yeah...and I haven't driven my car in about 4 months because of this and I'm having withdraws. I need it fixed asap it's killing me!
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Old Jul 25, 2010 | 12:28 PM
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Originally Posted by Paul Bell
So you're gonna be an expert at changing alternators!

Question (far all): When I did mine, I also replaced the AC compressor. I yanked out the sway bar as it seemed to be in the way of both items. Can the alternator be replaced with the sway bar in place?
Yes it can be replaced with the swaybar in place. When you are removing it just press against the fans a little to give you enough room to take it out.

I've never removed the alternator without having the swaybar in place. It might take a little more work but it can be done.
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