The alternator replacement thread, Fixed! |
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The alternator replacement thread, Fixed! |
VaccaRabite |
Aug 12 2018, 07:07 PM
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#1
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En Garde! Group: Admin Posts: 13,444 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
Waiting on the side of the road for a flatbed to take me home.
Engine ran great. Charging system not so much. Driving along. Lights started going dim. Car started bucking. Only 5 miles to home but it wasn’t going to make it, and no shoulders to pull over safe on the little farm roads. So I pulled into a spot I knew of and shut it down and parked it and now I wait. McMark had said earlier he wasn’t sure about the charging system. But the alt light was not on and no issues before now. So. What’s the alternator I need to buy? Maybe a new VR as well? I guess I should test the battery and make sure it’s okay too. Zach |
VaccaRabite |
Aug 13 2018, 09:09 AM
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#2
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En Garde! Group: Admin Posts: 13,444 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
Just did Spokes test of shorting DF and D+.
Battery went from 12.12 volts engine off to 11.87 volts engine on at idle. If I understand correctly even at idle I should expect to see greater then 12 volts with the VR shorted to Max Effort state. I’m guess the alternator is just dead. I also made sure the belt was tight, and it was good and tight. Going through grounds and don’t see anything too off kilter, though I have only looked at engine bay grounds as yet. This alternator, by the way, only had about 300 miles on it. It failed really quick. While I’m thinking about t, is there a way to bench test the voltage regulators? Zach |
ClayPerrine |
Aug 13 2018, 12:16 PM
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#3
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Life's been good to me so far..... Group: Admin Posts: 15,465 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille |
Just did Spokes test of shorting DF and D+. Battery went from 12.12 volts engine off to 11.87 volts engine on at idle. If I understand correctly even at idle I should expect to see greater then 12 volts with the VR shorted to Max Effort state. I’m guess the alternator is just dead. I also made sure the belt was tight, and it was good and tight. Going through grounds and don’t see anything too off kilter, though I have only looked at engine bay grounds as yet. This alternator, by the way, only had about 300 miles on it. It failed really quick. While I’m thinking about t, is there a way to bench test the voltage regulators? Zach A Bosch alternator is a B circuit alternator. That means that applying 12v to the field (DF) terminal on the alternator will make it provide maximum output, somewhere in the neighborhood of 15 to 18 volts. You should also hear the whine come from the alternator and an RPM drop on the motor. Zach.. check and make sure the relay board is not the culprit. Pull the 3pin alternator plug off the relay board, and with the car running, apply 12v from the battery positive post to the DF terminal. If you don't get 15 to 18 volts and a whine, I would replace the alternator and the wiring harness to it. There is a group sale on the harnesses going on right now in another thread. Buy a new Bosch alternator. A lot of the "rebuilt" alternators out there are just cleaned and maybe replace the brushes. |
VaccaRabite |
Aug 13 2018, 12:37 PM
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#4
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En Garde! Group: Admin Posts: 13,444 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
A Bosch alternator is a B circuit alternator. That means that applying 12v to the field (DF) terminal on the alternator will make it provide maximum output, somewhere in the neighborhood of 15 to 18 volts. You should also hear the whine come from the alternator and an RPM drop on the motor. Zach.. check and make sure the relay board is not the culprit. Pull the 3pin alternator plug off the relay board, and with the car running, apply 12v from the battery positive post to the DF terminal. If you don't get 15 to 18 volts and a whine, I would replace the alternator and the wiring harness to it. There is a group sale on the harnesses going on right now in another thread. Buy a new Bosch alternator. A lot of the "rebuilt" alternators out there are just cleaned and maybe replace the brushes. I'll check it, though it will be after the electrician for the house leaves. I bought the alternator and VR Bruce had. Its rebuilt but by a local guy that he trusts to do it right. If Bruce trusts it, so do I. Zach |
ClayPerrine |
Aug 13 2018, 12:45 PM
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#5
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Life's been good to me so far..... Group: Admin Posts: 15,465 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille |
A Bosch alternator is a B circuit alternator. That means that applying 12v to the field (DF) terminal on the alternator will make it provide maximum output, somewhere in the neighborhood of 15 to 18 volts. You should also hear the whine come from the alternator and an RPM drop on the motor. Zach.. check and make sure the relay board is not the culprit. Pull the 3pin alternator plug off the relay board, and with the car running, apply 12v from the battery positive post to the DF terminal. If you don't get 15 to 18 volts and a whine, I would replace the alternator and the wiring harness to it. There is a group sale on the harnesses going on right now in another thread. Buy a new Bosch alternator. A lot of the "rebuilt" alternators out there are just cleaned and maybe replace the brushes. I'll check it, though it will be after the electrician for the house leaves. I bought the alternator and VR Bruce had. Its rebuilt but by a local guy that he trusts to do it right. If Bruce trusts it, so do I. Zach If you were close to me, I would give you one of the 8 known good alternators I have sitting on a shelf in my attic. They all have wiring harnesses and the metal air deflectors installed. |
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