Early Cj5 horn restoration?

So this is the horn from my 56'CJ5. Anyone have any idea how or if it can be restored to operational condition? I don't know what part does what, or what part is what, but it looks pretty good to me for its age. I did put 12volts to it and nothing happened...so logically since I know very little about how it works, I took it apart.

Thanks for any help.



-Verne

 

Here is a pic of the back. I assume that the two threaded terminals with the doubled up nuts (at the bottom of the pic) on the back are for + and - 12 volts?

 

I'm interested also. Mine is apart just like yours but I think I burned the coil up.
Good luck!
Tommy

 

I would start by checking the coil to see if it's burnt out (use an OHM meter). If it is then you're going to have to replace it (perhaps parts out of a different old horn?) or your going to have to rewind the coil or you may be able to locate the burnt portion of the winding and just reconnect the ends. I haven't worked on a horn but I've fixed a number of similar coils by locating the burnt wire and unwrapping each end about 1/2 of a turn and then reconnecting the two ends. Yes, you will end up with one less turn but there's probably over 1000 in the coil so one isn't going to change anything.

There should be some kind of contacts in the horn that are used to make and break the circuit, they are what makes the horn buzz instead of just acting like a electro-magnet. If you're lucky the contacts just need to be cleaned.

 

Good advice from joe51. The horn is just a very loud buzzer. The coil is an electromagnet that vibrates the steel diaphragm - sort of like a loudspeaker that can only play a single note. The first thing to do is check that you have continuity through the coil. As joe51 mentioned, the wires often break where they go from their connection to the coil. I expect breaks here do not happen because they burn through, but instead because of metal fatigue in the unsecured part of the wire. Copper, like aluminum, will accumulate fatigue stress even from the smallest repetitive movements, and the loose part of the wire will fatigue the most.

Fortunately, as joe51 mentioned, you can often unwind a little of the coil to get some extra length, and reattach the parted wire. How are your soldering skills? The contacts are how the electromagnet turns on and off. The screw on the back of the horn can change the pitch of the horn a little by adjusting the distance between the diaphragm and the contact. When the horn is energized, the diaphragm is pulled toward the magnet. When it moves some, it breaks contact with the electricity, which de-energize the coil. The diaphragm moves back, making contact again. This happens a few thousand times per second, making the horn sound.

 

Before getting in too deep, have you tried adjusting the external setscrew?

Also, horn operation is very sensitive to voltage drop at high current draw. Use a "known good" source of power with plenty of amps...

And - if it's a '56 it's probably SIX volts.

 

Make sure your wires are polarity connected. Look very carefully and you will find a - and + stamped near each stud.

 

Thanks for all the replies. Should I track down a 6 volt battery? the Jeeps gonna be 12 volt, so maybe I am barking up the wrong tree? Does the Coil move or is it just the metal diaphragm that moves? I guess I also should to continue disassembly to clean up everything?

Its super cool to see how this thing works!

 

Just the diaphragm moves.

Yeah, I would go with a 12V horn, if the Jeep will have a 12V battery. The coil in the horn will pass twice as much current at double the voltage, and I'd expect it to not last long.

 

Sent you a PM

 

OK, thanks for the info! Posimoto, you will have a PM shortly!

 

Wow, i guess I lucked out, I wired mine up and it worked. (phew)