1926 Citroen B2 horn - Faine 456

By: Jon Faine

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Alerting the public to your undeniably dangerous approach, in a silly old car, can be achieved in multiple ways

The earliest versions were brass horns with rubber bulbs attached. The more elaborate and shinier the plumbing, the better to startle unaware pedestrians and stray chickens. I have picked up a few options along the years, but I think they are a bit twee and for a 1926 car they were already superseded by the availability of electricity to power any warning device.

Needless to explain, more modern contraptions boast simpler 12v horns that sound like trumpets or geese. There is little mystery to them and they have hardly changed in fifty years. Your average hoon, like most columnists in this august publication, would prefer little compressor driven air horns that play showtunes and only impress adolescents.


Klaxon is an American brand, but has become the name used to describe the early electric trumpet that makes a distinctive guttural noise. Because it is from across the Atlantic, it is totally wrong for my French car, but as I have not found any six volt French equivalent, it will do the job. Period photos of the Citroen B2 Caddy all show that it is essential to have a klaxon mounted mid-way on the driver’s side panel between the bonnet and the front door.

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Somewhere a while back at Bendigo Swap I stumbled on a genuine six volt Klaxon, an appliance that has become known by a brand name. Think google instead of internet search or Ugg boot instead of sheepskin slippers, Xerox instead of photocopier and Tesla instead of unsustainable and overpriced electric car. The main problem was that this example of the Klaxon was a sad wreck of a seriously neglected example and was showing no signs of life.


The cosmetics were easily addressed. Dismantling was just a matter of unscrewing everything visible and it readily fell apart. A day spent getting intimate with the wire brush and sandpaper then a couple of passes with a spray can of gloss black and it looked a zillion bucks. Job done, superficially at least.

The mechanism inside is deceptively simple – the noise is made by a small electric motor spinning a serrated disc against a rivet that is itself embedded into a wafer-thin diaphragm. As the current activates the motor it spins the serrated disc, that makes the diaphragm vibrate and the noise is amplified through the trumpet. The motor was non-responsive to power, so I tried the easiest repairs first and simply polished the commutator with very fine sandpaper wrapped around a needle file, and then cleaned the brushes with cotton buds dipped into methylated spirits. Bingo – apply power and it worked!


Any six volt instrument is going to be wobbly, especially one that is a hundred years old. That is why 12 volts came along – six are just not enough. But with perseverance and lubrication of the felt pads surrounding the bearings, some gentle easing of the distorted casing that must have happened years ago the motor now spins freely and my Klaxon makes something resembling the required noise – a bit like my late father’s gold medal snoring.


New gaskets cut out from 0.05" sheets complete the job, and with reassembly there is a very handsome accessory for the car – although the actual car it will go on might, just might, be finished in a few years time.


While fossicking through my horde of fancy bits I also found a lovely period correct SIFAM ammeter. I know it is wildly optimistic to be playing around with the fiddly bits before I have got stuck into the wooden frame or the body panels but I needed a sugar hit and some tangible proof of progress as everything else waiting to be done is really hard.

An afternoon tinkering and polishing is instant gratification and just what was needed to lift my sagging spirits. The ammeter came apart easily enough and the buffer rewarded my efforts by polishing up the bezel and metal case a treat. I also have a period cable driven speedo but that is a much bigger repair and restoration job and will almost certainly need to be outsourced.


Meanwhile, the rod brakes have all come back together, the fuel tank has been mounted on its supports, the steering box and shaft degreased, sanded, painted and reinstalled. It is so easy to type those words but that sentence represents a solid week of work. Making something as simple as the rods for the brakes, cleaning every thread, getting every cotter pin to fit – hours and hours of fiddling, some cursing and a lot of grunting… noises a bit like a Klaxon if the truth be told.



From Unique Cars #456, Aug 2021

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