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Dead short, please help!

Discussion in '308/328' started by Ferraritalian, May 3, 2020.

  1. Ferraritalian

    Ferraritalian Karting
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    Jan 19, 2019
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    Buddy was wrapping up work on my car and he was putting in a new battery. Says he barely touched the clamp to the wrong post by accident, barely sparked. Says the car now has a dead short. His research tells him that it likely toasted the voltage regulator.

    We started out with an alternator issue on this car and the nightmare it took to get to it. The idea we have to do this again is an awful thought.

    Any input here? Could it be something else?
     
  2. yelcab

    yelcab F1 Veteran
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    It could be something else, but it is likely the alternator. Remove the alternator connection to the 12V, does the behavior now change?
     
  3. mike32

    mike32 F1 Rookie

    May 13, 2016
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    First off check the battery switch to earth is not damaged, take a resistance reading from the negative clamp to the earth side of the switch- by connecting the positive to this it has full shorted to earth through this switch and might have burnt the contacts.
    With alternator disconnected, remove the fuses from the box- connect the battery with the ignition key in on position- replace the fuses one by one and hopefully none will blow. With all fuses back in the box start turning on lights, AC fan etc to load each fuse circuit. If you get a fuse that blows or something that does not work then it gives you some where to look.
    If every thing works then reconnect Alt and see how you go.
    With a bit of luck you might have just fried the battery switch to earth and this will give u all sorts of problems
     
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  4. versamil

    versamil Formula Junior
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    A battery switch if there is one, doesn't care which way a battery is hooked up. If you hook the battery up so you have a positive ground instead of a negative ground, none of the cables or switches are affected. Your DIODES in the alternator however ARE affected, and you popped a few diodes.Take Yelcabs advise and disconnect the alternator wire, and your short most likely goes away. Barely touched, barely doesn't matter- it's usually instant fail.
     
  5. Ferraridoc

    Ferraridoc F1 Veteran
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    Yep
     
  6. Brian Harper

    Brian Harper F1 Rookie
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    Agree with all of the above. But one good piece here is that the alternator (probably) doesn't have to come out. The diodes are in the voltage regulator and the voltage regulator on most Bosch alternators are both removable and available as a spare part. It's the (usually) black box on the back and is held in with a couple of screws. Maybe that's easier to remove than the whole alternator. Certainly should be cheaper.
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  7. Ferraritalian

    Ferraritalian Karting
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    Brian, super helpful point. I have a question for you. When I bought the car we thought the alt was bad and after moving Heaven and Earth to get the alt out, we found out that it wasn’t the problem. However, I still had the alt shop rebuild it, including replacing the voltage regulator. I remember researching it and seeing different listings different Bosch alternators, some saying the ‘79 GTS was different than others. When the shop ordered the voltage reg, he had the alt out and in his hand. But if I try to order a regulator ahead of Eventually getting to the alternator this time, I’m not exactly sure what part to order and from where. (feel free to insert snickers here) I did take one pic of the alt when it was out, but it didn’t show the regulator. I’ll post it here anyway.

    My question for you is, can you tell me what part/part number to order and even better, from where that would be dependable? THANK YOU.
     

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  8. Milkshaker0007

    Milkshaker0007 Formula Junior

    Sep 22, 2012
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    i know this is different as its a 328, but just like others have said the regulator is changeable whilst alternator is still in car like mine was when i replaced my regulator and overhauled the starter motor on the same day, all these individual parts are still available to make the repair yourself for less than £10.
    328, working great still over 7 years now since fitted. photos for reference to help others
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  9. Brian Harper

    Brian Harper F1 Rookie
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  10. Ferraritalian

    Ferraritalian Karting
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    See this is my problem. When I look it up on Google using 1979 GTS, its shows part #107396 for $74. When I look up the number 111786, the diagram makes reference to a 400 GT and shows the regulator for $26.19. Both for Bosch. Both drawings are showing the little both screwing to the back of the alternator with 2 screws. Not sure why this is so imprecise.


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  11. Ferraritalian

    Ferraritalian Karting
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    The more I look the more confused I get. The picture of the square “box” that Brian shows seems familiar to me. All the searching I’m doing shows the odd shaped design of the 328 picture that milk showed. Superperformance just shows that too. I’m starting to think we will have to get it out first to be sure, then order a regulator/


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  12. Ferraritalian

    Ferraritalian Karting
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  13. mike996

    mike996 F1 Veteran

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    Take it out to be sure. There are replacement alternators that have a different configuration than what was originally installed. Unless you KNOW what's in there, bite the bullet and pull it.
     
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  14. BigTex

    BigTex Seven Time F1 World Champ
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    I have always had better luck in repairing the alternator, that is damaged than going in search of a new unit.

    I'm pretty fast at getting it out too....sometimes I drop the engine mount bolts and raise it for clearance..
     
  15. Brian Harper

    Brian Harper F1 Rookie
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    Actually, that is absolutely true. There's no guarantee that the original part will fit whatever you have now. It comes out in just a minute after you get to it. Do disconnect the battery before pulling it out.
     
  16. Patrick Dixon

    Patrick Dixon Formula Junior

    Mar 27, 2012
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    ... and connect it up CAREFULLY when you put it back ...
     
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  17. Ferraritalian

    Ferraritalian Karting
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    Hmmm... and apparently that regulator box in the back of the alternator that might have been SO convenient is blocked by the alternator heat shield.
     
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  18. Milkshaker0007

    Milkshaker0007 Formula Junior

    Sep 22, 2012
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    just a bolt to undo from the shield/manifold(header) to remove which you will have to feel as i don't think you can actually see it.
    ---just one and that's it, you will have full access to remove black rear cover on alternator and then two screws to remove the the regulator and order the correct one. easy job. keep going your so much closer now OR you could remove the whole unit again :)
    if i was close i'd do it for you :)
    post up a picture of the regulator when removed so we can see what type is in there.
    cheers
    paul
     
  19. Ferraritalian

    Ferraritalian Karting
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  20. Milkshaker0007

    Milkshaker0007 Formula Junior

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  21. Milkshaker0007

    Milkshaker0007 Formula Junior

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    these videos from Martin are great-Westronicslrl
    this one to re build starter motor (ours-various-Bosch) if links don't work just copy and paste



    alternator re build (just bushes)

    in more detail you get the idea

    There are many more, just plough through them at your leisure, once you've re built one starter motor/alternator they are all the same, just slight variations.

    all these videos on Martins site are great tutorials and step by step re build guides https://www.youtube.com/channel/UCTDErideqzqIZgWYgK-TMkQ

    He did have an EBAY shop selling all the parts, not sure if its still there though.
     
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  22. Patrick Dixon

    Patrick Dixon Formula Junior

    Mar 27, 2012
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    If you've disconnected the alternator, you should no longer have the dead short. If you do,the problem is elsewhere.
     
  23. Ferraritalian

    Ferraritalian Karting
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    Alternator shop says diodes are bad and he can’t get them. Taking it to another shop who Ive had good luck with.
     
  24. BLACK HORSE

    BLACK HORSE Formula 3
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    Steve, you can call this guy who specializes in Bosch alternators and starters... This guy Dean rebuilt my alternator about 6 months ago, he may have the parts that you're looking for... Good luck!

    http://deansautoelectrical.com/
     
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  25. Ferraritalian

    Ferraritalian Karting
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    Rob, thanks very much for the suggestion. Today I’m taking the alt back to the place who rebuilt it last Spring, hoping that they can get it done. Failing that, I’ll look at shipping it out to a place like your recommendation.
     
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