Getting a set of horns to work - 1948 Chrysler

[timecapsule]

My friend had these horns and asked if I could get them going again.  He got them at a swap meet years ago and he knows nothing about them.  I'm not certain but I think they are pre-war Mopar.  My reasoning is, I have a '48 Chrysler.  All the components look pretty much the same.  However the Autolite relay has 3 prongs.  My relay has 4 prongs. so I'm thinking that in 1946, Chrysler went to a 4 prong relay.  My parts manual is '46-'48 and it only shows the 4 prong relay.   One trumpet has a longer section to it.  My '48 horns are the same length.  However the tube coming off the horn that makes a 90 degree turn to connect to the trumpet part on these horns are the same length.  Where as on my '48 one is about 4-5 inches longer.  In the end you'd get the same effect with the two tones.  So given these differences, makes me think that they are pre-war Mopar horns.  This is just my guess so please correct me if I'm wrong.  No marking on the horns but the relay has the Autolite logo. I'm using my volt fully charged battery as my power source and just a regular toggle switch. Pretty sure I have it wired correctly since I got the one horn working good now.

 

Both were corroded with rust from being filled with water at one time, including the relay.  I took everything apart and one horn wasn't in too bad a shape and after some time I finally got it to sound like a horn.  But the other is being stubborn and likes to smoke a bit.  I've realized that dialing these horns in is a very finicky and sensitive process. 

 

I think the issue is where the coil of wire is in the armature case, it was completely full of rust.  The thin brown paper was in a million pieces.  I'm assuming the paper was an insulator.  If you zoom in one of the pictures you can see several bare sections on the coil of wire. 

 

I've coated the armature housing for the coil of wire, with that "liquid tape" stuff.  Basically liquid rubber.  The same stuff you dip the ends of plyers into to recoat them.  I tried to cover the bare sections of the wire with the same stuff.  Then I tried to get the wire back in the housing.  As you can imagine. it wouldn't all go back in.  So when I send power to the horn, the centre shaft tries to go down but the wire is sticking up a bit and keeping it from going down and so all I'm getting is a sound like a tap of a screwdriver on the bottom of a can sort of thing each time I hit the switch. 

Any suggestions?

Can I cut the solid wire and shorten it a bit so it will all fit in to the armature housing, and then resolder the end to the connection?

Is it probable that the wire is shorting out on the housing?  Is that why it was smoking?  Or am I barking up the wrong tree?

 

I'm confident that I reassembled the rest of the components correctly with the insulator spacers in the right place.   

[EmTee]

Can you buy new wire and wind a replacement coil?

[timecapsule]

25 minutes ago, EmTee said:

Can you buy new wire and wind a replacement coil?

Not sure, But I'd still have the same issue of trying to get it all packed in there snugly. Obviously it was done with a machine at the factory.

[timecapsule]

This is how the wire looks on the other horn, neatly packed in with a couple securing tabs coming through a couple slots from the other side.  I still have those two tabs, but I'm doubtful I would get it all back in looking the same with those tabs holding the wire in place.

[Bhigdog]

Modern magnet wire has insulation a fraction of the bulk of the old fabric insulation. You would have no problem fitting the same gauge and length wire in that space.

Modern magnet wire insulation comes in various temp range insulation. Twer it me i would use the highest temp. I forget the chemical name of the higher temp type  insulation. Let google help you out. I,m guessing mcmaster has what you need

 .......bob

[Bhigdog]

39 minutes ago, timecapsule said:

Not sure, But I'd still have the same issue of trying to get it all packed in there snugly. Obviously it was done with a machine at the factory.

Make and wind it on a bobbin. Tie/tape it off just like the factory did and insert in the case like original. Bob

[timecapsule]

Thanks for the suggestions guys.  So I'm guessing that you're in agreement that the wire is shorting out on the armature housing? 

I did a quick search on line and it seems that it is sold by it's diameter on Amazon.  McMaster Carr list it by gauge and O.D.  So when measuring what I have, do I put caliper on the bare wire?  I'm wondering how critical getting an exact replacement in gauge/O.D. is, as well as the exact length?

 

 

 

Edited November 30, 2022 by timecapsule (see edit history)

[Bhigdog]

You need it by bare wire gauge. Google can convert dia to gauge for you. Total length is important. That should give you the correct resistance and number of turns in less space.......bob

[Bhigdog]

23 minutes ago, Bhigdog said:

You need it by bare wire gauge. Google can convert dia to gauge for you. Total length is important. That should give you the correct resistance and number of turns in less space.......bob

 Because of the thicker fabric insulation the number of turns may be a bit off but it should not matter......bob

[Rusty_OToole]

Electronics dealers sell coils of wire like that. For speakers or electromagnetic coils. It would be nice if you could find one the right size. I don't recall where I saw them it was online a few years ago. A search for electromagnet coil or speaker coil might turn up something.

[Bloo]

Use the same size wire and the same number of turns. If it's too loose in there tape it a little more.

9 hours ago, timecapsule said:

So when measuring what I have, do I put caliper on the bare wire?

A micrometer would be better, but that will probably work.

 

9 hours ago, timecapsule said:

I'm wondering how critical getting an exact replacement in gauge/O.D. is, as well as the exact length?

Maybe not that critical since it's just a horn. If you really want it to work right on the first try, duplicate the wire size and the number of turns exactly. I can assure you it wasn't chosen at random.

 

10 hours ago, timecapsule said:

But the other is being stubborn and likes to smoke a bit. 

 

9 hours ago, timecapsule said:

So I'm guessing that you're in agreement that the wire is shorting out on the armature housing? 

I don't know. These draw truly massive amounts of current when the points are stuck, and would burn up on short notice. If its getting hot instead of honking, yes a short to ground could do that, or a shorted turn, but it would do it anyway if the points weren't vibrating. My guess is if it smoking and the points aren't stuck, something is mechanically wrong.

 

[timecapsule]

Thank you guys.  You've all been very helpful.  I'll take a reading on the diameter and the length of that wire and my friend who owns the horns said he'd buy some, once I give him the dimensions.  We have a local shop here that rebuilds vintage car generators, starters, converts generators to alternators, etc etc.  They rebuilt the 6 volt generator on my '48 Chrysler .  We can probably get it from them by the foot.   

[JACK M]

Is there anybody out there that specializes in these old horns?

I have given up on mine.

[Rusty_OToole]

Not much call for horn repairs since it is usually easier and cheaper to buy a new one. Not always practical if you want an identical one for your vintage car. But used ones turn up and they never seem to wear out.

[timecapsule]

4 hours ago, JACK M said:

Is there anybody out there that specializes in these old horns?

I have given up on mine.

What seems to be the problem with your horns?  Similar to my issues?

[timecapsule]

21 hours ago, Bhigdog said:

Make and wind it on a bobbin. Tie/tape it off just like the factory did and insert in the case like original. Bob

Thanks for that advise. I had a piece of wooden Dowling about the same size as I needed, and for a shoulder ( so to say) on the one side I used a role of electrical wire.  it fit nicely over the dowel.  Then I put a hose clamp on the opposite side, to keep it from moving outward.  For the other shoulder I used washers, large rubber gromet, large nut and a hose clamp.  It looks ridiculous, but it did the job.  I stretched out the old wire so it was almost straight after releasing the one end from it's solder connection.  Then I carefully wound it tight around the dowel, keeping it as uniform as possible.  I then slipped it into the body that holds in in place.  Wired up the horn again and it works great now.   So in doing so, I'm guessing that just by good luck, none of the bare wire sections are touching the sides or bottom of that body.  

 

So my friend might not buy the wire now.  It's up to him.  It was more just an exercise to see if I could repair it ( thanks to you guys)  and to learn how it was designed.  The horns will probably go back into a corner of the guys garage, and never be touched again until I'm long gone.  But I will tag them as being working with todays date. 

[Bhigdog]

23 minutes ago, timecapsule said:

Thanks for that advise. I had a piece of wooden Dowling about the same size as I needed, and for a shoulder ( so to say) on the one side I used a role of electrical wire.  it fit nicely over the dowel.  Then I put a hose clamp on the opposite side, to keep it from moving outward.  For the other shoulder I used washers, large rubber gromet, large nut and a hose clamp.  It looks ridiculous, but it did the job.  I stretched out the old wire so it was almost straight after releasing the one end from it's solder connection.  Then I carefully wound it tight around the dowel, keeping it as uniform as possible.  I then slipped it into the body that holds in in place.  Wired up the horn again and it works great now.   So in doing so, I'm guessing that just by good luck, none of the bare wire sections are touching the sides or bottom of that body.  

 

So my friend might not buy the wire now.  It's up to him.  It was more just an exercise to see if I could repair it ( thanks to you guys)  and to learn how it was designed.  The horns will probably go back into a corner of the guys garage, and never be touched again until I'm long gone.  But I will tag them as being working with todays date. 

My pleasure. Thanks for the report....bob

[JACK M]

1 hour ago, timecapsule said:

What seems to be the problem with your horns?  Similar to my issues?

Yes, once in a while I can get a squeak when they are on the bench, but they both pretty much act like they are shorted.

There is not a relay, and the spring under the button seems to have lost its integrity because of the short.

The button offers a ground directly to the horns, so I have unhooked the power to them. (they have to be insulated from a ground).

I have seen some pics of how the column comes apart and I don't think I want to get involved in that.

So, If I ever can get them rebuilt, I will probably wire up a relay and a separate button.

In fact, I may put a horn under the car somewhere and just use the stock ones for their good looks.

[vintage1]

Try The Horn Works, https://www.carhornrestoration.com. for horn repair and restoration.

 

[JACK M]

12 hours ago, vintage1 said:

Try The Horn Works, https://www.carhornrestoration.com. for horn repair and restoration.

 

Thank you for this.

I would be right on it if they hadn't made it so clear that they only do 12-volt horns.

When I get the car back up here first of the year, I might call them to see if they know anybody that does 6-volt stuff.