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Horn Workings And Adjustment

Discussion in 'Early CJ5 and CJ6 Tech' started by baldjosh, Sep 4, 2019.

  1. Sep 4, 2019
    baldjosh

    baldjosh Member

    pacific north west
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    Back when I started the rebuild on the Jeep I decided to paint and powder coat the horn...because you know...cart before the horse. I never tested it after putting it back together...just left it on the shelf for later. I'm now at the point to install it and guess what...no BEEP BEEP.

    thumbnail_20190903_095032[1].jpg

    I did a few searches here and it seemed a couple people have been interested in the workings and that at one time there was a thread covering this but its long gone, so I thought id share the information I learned while getting mine working. I'm not sure what make or model the horn is or if its the same as all horns of my Jeeps vintage ( '59 ) and I'm super open to any comments or corrections.

    This super technical computer aided drawing of the basics of my horn shows the working parts.

    Untitled.png

    Power is supplied through the horn to the horn button, that when pressed grounds the circuit sending power through the windings to create an electro magnet that pulls the diaphragm in (down in my pic ) The striker? first hits what looks to be phenolic board holding a point, breaking the points, and killing the power to the magnet. the striker then hits the center adjuster, checking the diaphragms momentum and the diaphragm returns to its normal position where the points close and process is repeated. hundreds of times a second??? don't know but its a lot.

    thumbnail_20190903_095023[1].jpg

    I pulled the six bolts around the outside of the horn and it just fell open.

    thumbnail_20190903_095459[1].jpg

    When taking the metal point adjusting arm off the tension spring shot out , I found it best to back out this screw first so it wouldn't sproing all over. You should have continuity from the + post to the points, if not then the wire has been broken (or the point is really corroded)

    thumbnail_20190903_095901[1].jpg

    I shined up my points and reassembled making sure all the little rubber insulators went back in the proper locations. It was much easier to thread the adjuster screw with spring in first (the little spring is a strong one and kind of challenging ) I left the points adjustment screw just started in the adjustment arm so the points are open and ready for adjustment when reassembled. Also the center adjuster should be left backed out for adjustment as well.

    Reassembly shows how the striker will hit the phenolic tab

    thumbnail_20190903_101142[1].jpg

    Now with some jumpers and an ohm meter hooked up to the + and – posts of the horn I tightened the points arm until the points just made contact, I then tightened the screw a 1/4 turn more. Much less and just moving the horn around would cause it to lose continuity from vibrations, any tighter seemed unnecessary and it seemed it might put more stress on the parts and keep the points closed for too long.

    thumbnail_20190903_101918[2].jpg

    I then threaded the center adjuster in until I felt it just touch the striker, and then backed it off a half turn and locked it in place with the nut.

    thumbnail_20190903_102014[2].jpg

    with the ohm meter hooked up I could press the diaphragm really hard and see the horn lose continuity

    thumbnail_20190903_102342[1].jpg

    I later fooled with the diaphragm stop screw, turning it out more made it sound like it was tearing itself up, on my horn, the 1/2 turn out seemed to be the sweet spot.

    Not a lot to go wrong inside the horn, hopefully non op horns out there just need an adjustment, and I'm sure all this could be done as well without even taking it apart as long as the points are clean and make contact. I took mine apart for powder coating but if I hadn't needed to, knowing what I now know, I would just hook the ohm meter to the horn, check for continuity, and then adjust.

    Hope this helps someone.

     
  2. Sep 4, 2019
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    A thing to remember is that horns must be installed on a resilient mount. If they are mounted rigidly, they don't vibrate properly and won't work right.
     
  3. Sep 4, 2019
    baldjosh

    baldjosh Member

    pacific north west
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    Oct 24, 2017
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    Thanks for mentioning that (y)I read in another post where you mentioned that same point but forgot to add it...the horn really does vibrate/move a lot when its doing its thing!
    also fixed the stupid you tube link...hope it works now
     
    Last edited: Sep 4, 2019
  4. Sep 5, 2019
    Rick Whitson

    Rick Whitson Detroit Area 2024 Sponsor 2022 Sponsor

    I live South of...
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    Hit it with a hammer, just kidding, but sometimes you just need to get it started then adjust the diaphragm. Motorcycles had the same problem with their horns.
     
  5. Sep 5, 2019
    Keys5a

    Keys5a Sponsor

    Florida Keys
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    That should be a Sparton SA (or clone). Yes, they are pretty simple, but are so satisfying when they make the right "Beep Beep". I believe 1970's Mopars used this same horn, only painted purple.
    -Donny
     
  6. Sep 5, 2019
    Focker

    Focker That's a terrible idea...What time? Staff Member

    WA
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    Excellent write up and pics!
     
  7. Jun 6, 2020
    ChrisP

    ChrisP New Member

    International
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    Hi everyone,
    This weekend I plan to restore the Sparton horn from my 1957 CJ5. Luckily I came across this post because the horn was already open when I've got it and I have no before pictures.
    I have all parts cleaned and I am ready to put everything back. The hard part begins!
    As you can see, the cable to the phenolic board needs to be welded.
    Main issue is about the arm and the order of the insulators. I believe there is 1 squared insulator missing.
    I sent a PM to Josh asking for help and I thought to reopen this post so we can all benefit from it.
    Below some pictures of the horn and the parts I have.

    [​IMG]

    [​IMG]

    [​IMG]

    Thank you very much in advance.
    Regards,

    Chris
     
  8. Jun 6, 2020
    Admiral Cray

    Admiral Cray I want to do this again.. Staff Member

    Bainbridge...
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    Chris, you still need to give me one of those side bolts... :whistle:
     
  9. Jun 6, 2020
    ChrisP

    ChrisP New Member

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    I wish I could Fred. Let me talk to a friend who might have some bolts like those.
     
  10. Jun 6, 2020
    wasillashack

    wasillashack Member

    Wasilla, Alaska
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    If you need a very loud horn use a 6 volt horn on 12 volts, we discovered this in high school when we installed a small block Chevy in a '53 Chevy and converted it to 12 volts, leaving the original 6 volt horns installed. I am not trying to offend 6 volt Jeep purists, any 6 volt horn will do. Good Luck!
     
  11. Jun 7, 2020
    baldjosh

    baldjosh Member

    pacific north west
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    I didn’t have any more pics of the horn…its pretty simple in there… so I just took it apart again to get some more pics of the internals. No guarantee this is how its supposed to be… but im pretty sure its dang close.

    Ive got 3 square grommets (?) with a collar
    thumbnail_20200607_095234.jpg thumbnail_20200607_090722.jpg
    3 round plain ones thumbnail_20200607_095228.jpg


    And 1 round one with a collar
    20200607_095721.jpg
     
    Focker likes this.
  12. Jun 7, 2020
    ChrisP

    ChrisP New Member

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    Wow Josh! I have no words! I was expecting some help like we always get in this forum but not such detailed help! No even thought about asking you to open your horn again. Thank you. This is great. Exactly what I need. I will review what I am missing and continue the rebuilt. Will post my work once it is completed.
    Have a good day
     
  13. Jun 7, 2020
    baldjosh

    baldjosh Member

    pacific north west
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    You asked a pretty good/important question that I failed to address in my original write up...thought it would be good info for future horn repairs...I love keeping old junk alive!
    cant wait to hear the Beep Beep :beer:
     
    ChrisP likes this.
  14. Jun 7, 2020
    Admiral Cray

    Admiral Cray I want to do this again.. Staff Member

    Bainbridge...
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    My horn... (and no comments from Don)...

    [​IMG]

    And if you look carefully (right bottom) you can see what I just discovered a broken wire. So that's why it wasn't working...

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    Notice the missing bolt (somewhere in my shop)...

    [​IMG]
     
  15. Jun 7, 2020
    ChrisP

    ChrisP New Member

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    I spent the weekend at my in laws. I could just clean all parts. I drove 2 hours back home and I couldn’t resist stopping at the shop to weld the broken cable and follow Josh detailed instructions. First attempt: Horn 1 - Chris 0. No beep. I open the horn again but everything was in place. I now followed above instructions line my line. Very important to adjust point screw looking at continuity.
    Attempt #2. 9pm already. Here is the result.



    Tomorrow, painting and final assembly!
    Thanks Fred for the photos and Josh for your guidance and detailed steps.

    Regards,
    Chris
     
    baldjosh and Fireball like this.
  16. Jun 8, 2020
    baldjosh

    baldjosh Member

    pacific north west
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    YESSS!!!!:clap:
     
  17. Jun 10, 2020
    ChrisP

    ChrisP New Member

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    Now the job is done. I primed and painted. This weekend it will be mounted on the ‘57.
    Please comment If something can be improved. I believe the bracket goes that way but I am not completely sure. Also the spring might be unpainted?

    [​IMG]


    [​IMG]


    [​IMG]


    [​IMG]


    [​IMG]



    Thanks and regards
    Chris
     
    Fireball likes this.
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