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Klaxon Horn Maintenance

Started by 29UJohn, February 15, 2013, 09:31:58 PM

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29UJohn

There is a good article on Model A Klaxon Horns in the December 2012 Skinned knuckles magazine (Vol 37 - No. 5).  It covers overhauling and tuning up the Klaxon "Ahh-Ooo-Gha" horns, like the ones on our 28-29 Plymouths.  One interesting recommendation was to apply a film of grease to the face of the agitator to improve the sound.  I tried it and it works well.
John
1929U 4 Dr

frankp

Thanks for that info, John.  Mine was sounding a little sick last fall.  frank
frank p

racertb

Is the agitator the flat diaphram vibrating piece or something else?

SDGlenn

#3
My 29 Coupe has the Klaxon horn, (I always thought it was a Klaxon anyway).  It does not go "Ahh-Ooo-Gha".  Is that the right sound? Or is something wrong with my horn.  I always thought the " Ahh-Ooo-Gha" type horn was only on the Ford Products?  I always thought the "Ahh-Ooo-Gha" horn was run with a motor inside? Could someone post a picture of their "Ahh-Ooo-Gha" horn, and what info is on the horn? Maybe mine had been changed in the past? Maybe mine just need this maintenance.? I'll try get to my 29 model and check the same.
Thanks
SDGlenn
SDGlenn

aussieQ

My 28 makes an "Ahh-Ooo-Gha" sound, well sort of, sounds a bit sick. I'll have to try the grease trick on the face of the agitator; once I know what that is.

Gary S

Tinkeys

I believe these horns have a rotating motor , the other type have a vibrating motor ,hope this helps !!

Old Man

#6
The wierd 'up and down' sound was made by the sudden speeding up of a motor and then the slowing down of the motor when current was cut. The motor has a pawl on the end of it's shaft and this pawl runs on a toothed piece of hardened steel. That produces the raspy sound. The steel toothed piece is fixed to a round very thin spring steel diaphram that works like the paper cone in an audio speaker. It serves to amplify the sound. If you hold down the horn button the pawl will just run round the teeth and make the the center sound,the 'OOOOOOO', for as long as you hold the button. Then when you release the button ,the 'GAAH', is actually unpowered. BTW the word Klaxon is French for 'horn'. Klaxonnez means to honk a horn. Pronounced "clacks-on-a" ,long 'a' not a short 'a'.        

racertb

My Klaxon 12C on my '29 (supposedly correct according to the parts catalog) is an ahh-oo-gah horn with the rotating motor.  So what part is the "agitator"?

Old Man

#8
I suspect they mean to put grease on the pawl and the toothed device where they run on each other? I would use modern silicone grease because it will not melt and run with engine heat. Never tried that with my '29U. Be interesting what the outcome would be if everybody who has a motor driven Klaxon horn on their Plymouth on this site tries it.
 Another BTW. These motor driven electric horns were simply an advancement of previous hand operated horns. If you look at some of the 'teens and 'twenties cars at a show,Model Ts included, you'll see a horn mounted beside the driver that has a plunger sticking out of it's top. Pushing down on this plunger produces the same 'AAHOOGAH' sound. They just added an electric motor to it. 1930 was about the watershed for motor driven horns versus vibrators. I assume the industry found the cost of making the motor to be not cost effective and moved to the vibrating relay type which we still have today.
 I've never had good reason to put this on the net,until now, but I thought you guys would like it. I've had an original wooden shipping box for a Klaxon 8 horn for many years. I've never seen another in the 40 years I've had it. It appears Klaxon,which I believe was a division of GM, shipped their horns in 1/4" thick wooden boxes. I do not know if this was a replacement shipped to a dealer or the factory got them this way as well.            

SDGlenn

It is amazing what will pop up on this board. Great pictures old man, also, I really like your take (insight) on Plymouth items. You always seem to know and understand every item posted here. Great Job. Were you once an "Old Man" that worked at the factories when these cars were built? Take care or you
SD Glenn
SDGlenn

Old Man

#10
No I never worked at an automotive factory. Just a hobbyist. But I have done all the work on my own cars,antique and daily drivers, since I was 16. Which would make it 53 years (!!!).             

imoore

From my experience these horns require a good power and earth. My horn sounded very sick. sometimes it would sound reasonable and then it would sound like 'a dead cow' ( as my mate puts it).
So i have now fitted a relay into the system as well as direct lines to a good power and earth. I also bypassed the amp gauge.
It's now very loud. But the Arr and Ghh are not so noticeable.
Mines a Klaxon 8C

Ian
1928 Q tourer (Holden bodied)
Several vintage stationary engine

Old Man

#12
The sound is adjusted by the locked screw on the back of the 'can'. If your version doesn't have an external adjustment it wil have an internal one. Take off the 'horn' by removing all the screws around the skirt. If I remember correctly there will be a locked screw on the 'ratchet' somewhere. If this is too 'tight', the AAHH and the GGAHH will be of short duration. The tension needs to be slackened up so the motor will run more freely and the AAHH and GGAAHH will take longer. The center OOOOO is run by the motor current,and your finger on the horn button, and will be the same regardless. Also the moving pawl has to centered on the toothed gizmo. Make sure it's lined up. And rub 3 in 1 oil or some other light oil over everything including the circular sound disc. And as previously mentioned it appears a slight application of silicone grease on the toothed gizmo and the pawl will make a difference. I suspect it will free up the movement by a percentage. And of course it goes without saying to put a couple of drops of light oil on the motor bearings. I just thought of something else. (It's been some time since I worked on one of these.) There is originally a thin cardboard gasket around the skirt. I suspect if this is not there it may 'ground out' some of the sound. The disc may be able to vibrate more freely and produce a louder sound with the gasket in there. Maybe they knew that when they made it. It kept water out but they may of found out it made the sound louder as well. Just as another thought perhaps a gasket on either side of the disc may produce a louder sound? In any case it's the rubbing of the pawl on the toothed thing that produces the sound but the disc works like a speaker cone in a radio and vibrates to amplify the sound. It must be free to vibrate as much as possible. The front of the horn is a megaphone if I'm not mistaken.