1955 Chevrolet BelAir - Horn Restoration

[Milt Packard]

I am searching for information on how to restore the 2 horns on my 1955 BelAir. 

I know there are companies out there that do this, I do not wish to 'cut-in' on their business, but I'd like to my own restoration as well as gain insight as to how horns work. 

I have a sand blaster, good drill press and vice, access to a gasket shop that will make the paper gaskets.

I have taken the round, half-moon cover off to reveal the electric parts.  I gave the assembly a quick sandblast to knock off 68 years of light rust, (700 grit media is almost a powder). Used a blow gun and shop vacuum to remove any media, paint or rust after blasting. 

The solenoid does work, it will click and light a bulb that I connected to the spade terminal.  The horn makes no sound. The part # on the casting indicates this is the high tone side.

Does anyone have a checklist to test components or next steps in the restoration process?

[JACK M]

I never was able to find horn restoration people.

[1957Birdman]

Milt,

Let me say upfront I am no expert on horns in general or Chevy ones in particular. Having said that I was able to refresh the horn on my T-Bird, which uses Sparton horns. Your horn, like the Sparton on my car, appears to have points (like ignition points) that get corroded over time. If you loosen the nut in the middle of the horn, you should be able see the points and then file or sand them to clean them. That nut actually adjusts the horn. Too tight or too loose results in no sound. 

Once you have cleaned the points then you can connect the horn to a twelve-volt battery and adjust until you get sound. I would adjust and then touch the wire to one of the connectors on the horn, assuming the other wire is already connected. 

I am almost sure that is the problem, as the components in the horn look to be in pretty good shape. If it is anything else than someone else with more expertise will have to help.

Good luck,

Lew Bachman

1957 Thunderbird

[Bloo]

Before taking it apart, I would lightly drag a tiny file, like a points file or maybe a nail file through the points lightly if it will fit. Maybe one or 2 drags at first. Less is more. Try pressing down on that thing in the middle to open the points. Avoid anything sandpaper-like because it could leave grit behind, and that causes the points to burn. Afterward, drag paper soaked in brake cleaner or some volatile solvent through the points to be sure you aren't leaving trash in there. Isopropyl would work too. See if it honks. If a tiny file won't fit, I'd try just the paper soaked in brake cleaner. If that doesn't work, you will have to loosen or disassemble, and then readjust from scratch as @1957Birdman advised.

 

The relay clicking is a good sign, but it doesn't necessarily mean it works. The points in it might need the same treatment I described above. I would test these horns by connecting them directly to a car battery. That leaves the relay out of it.

 

I think sandblasting that internally was ill advised, even with such light media. Magnet wire insulation of the era is very fragile. Speaking of insulation, you'd better do something about that bare spot on the white cloth wire. It looks close to ground. Maybe a little "liquid electrical tape" applied with a toothpick? Good luck with it. Let us know how it goes.

 

[Milt Packard]

Excellent suggestions.  I will complete them by Wednesday night.  Winter break concluded tonight, I am happy that I have a great job to go back to tomorrow!!!!  I have the electrical tape in a bottle and have a full run of small thin files at work.

 

[Milt Packard]

Gave it a dose of brake cleaner, blew it all out.  Used the thin file on the points.  Did not apply the liquid tape to the bare wire yet.  Adjusted the large nut (took this in very small turn movements) and was not successful at making the horn make any noise. 

[dodge28]

The proper procedure was to soak in Vapor Rust over night and wash off with warm water and blow dry. Use a points file to dress the contacts . Adjust the big nut up or down slowly while touching the terminal with voltage. Keep trying until the horn blows. Those horns are bullet proof. Better than Lucas.