One of the little projects that I've taken care of on my project was the horns. The Pumpkin has dual horns but neither of them worked. The horns aren't the same, one is low pitch, the other high. I did a search and located three of one and none of the other. I forget which was which.
Looking at the aftermarket horns that are available, they all look pretty cheap, so I looked at maybe repairing the horns I had.
The horns have two halves that are riveted together. The first thing you have to do is separate the halves. There are six rivets that need to be either drilled out or ground down. Either method will work, then drive out five of the rivets, there is a sixth rivet located in the horn part of the horn that is not really a rivet but part of the aluminum casting, this will have to be thru drilled so a screw can replace the rivet on reassembly. The rivet that is located under the horn's mounting bracket will have to be ground down, you can't get to it with a drill bit. I used a Dremel tool.
Once all six rivets have been removed you can separate the two halves. I used a thin blade putty knife to separate them to keep from damaging the gaskets. If you do damage the gaskets, I doubt it's a big deal. You can make new ones from thin card stock (file folder) or something similar. I'm not sure you even really need the gaskets.
When you get the halves separated, you'll see the horn is really simple inside. Basically it's a diaphragm that is sandwiched between the two halves. You can set this off to the side, along with the half of the horn that is just a casting.
The other half of the horn contains the "works".
Looking at the working half of the horn you'll see there is a set of contacts. Check these for continuity. If you know everything else in your horn's system is good then chances are you are going to have an open circuit. The contacts need to be cleaned.
Cleaning these contacts is the same as cleaning a set of points in the distributor. Take some fine sandpaper or emery cloth and run between the contacts. Once you do that run some paper between them to remove any remaining grit. Check for continuity again, if you get continuity your ready to put it back together.
As they say, reassembly is the reverse of disassembly. Place one gasket and the diaphragm on one half, then place the second gasket and other half on top of the diaphragm.
To finish reassembly you'll need (5) 8-32 X 3/4" screws, (1) 8-32 X 1/2" screw, and (6) 8-32 nuts & lock washers. The short screw goes in place of the drilled out rivet in the horn opening. I used socket head capscrews because their look mimics the original rivets and the allen head is easy to tighten in the tight areas. I also used nylok nuts so didn't need lock washers.
Once everything is tightened up, reinstall and hook up the wiring. You should be good to go.
While it's apart would be a good time to detail the horns if you want.

 

Right on Mike!! Thanks.

Both of my OEM horns were dead and were replaced by the PO with cheapo air horns. Luckily he left the OEMs installed and I still have'em. I'll do up your how-to now that I know what is going on inside the little buggers.

Bookmarked for future reference!

 

2x on the Right on Mike!

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Thanks for the great info! One more project to add to the ever growing list.

 

One thing I should add, the contacts, unlike points in a distributor, have some pretty heavy spring tension. When I cleaned them I used a small screwdriver to take the tension off them a little bit. That way I could move the sandpaper back and forth between them. If I didn't do that the sandpaper wouldn't move, it was clamped between the points.

 

OUTSTANDING!!! I have never taken one apart,,, always had an extra or 2 layin around,,, but I like this better!!
Thanks and Great Job!
Joe

 

Nice write up Mike!!

My horn used to work. I say it used to... when I connected the wire to it it was constantly on lol. So it stayed unhooked and I used the pipes to sound off It worked. Plus the horn sounded kind of puny. It doesn't work now though and I've got some air horns in there. Sounds like a dang train even though it was supposed to be the lower tone variety. :/ I'd hate to hear what the actual train version sounds like! Who knows I might rebuild the factory one. If I do I'll be using this guide!

 

Glad you posted this! I used to think horns were a throw away and replace part. I learn a lot on here every day, glad I found this place.

 

They're pretty much supposed to be throw aways, that's why they're riveted together. But when you can't find any NOS and don't want to use the plastic Chinese POS, you have to get creative.

 

I'd give ya reps, but I've given them too recently. Nice write-up

 

Thanks Devin.

 

Nice write up! I have a question for you though, do the horns still sound softer than a late model horn? I'm wondering if my horn on my truck just sounds "puny" like sleepy said because it was made that way, or its worn out? I was behind a texter the other day and I beeped and they didn't even look up cos my horn was so soft.

 

In those instances I wish it were lawful to use the chrome horn!

 

It's been so long since my horns worked I really don't remember what they sounded like so many years ago. But now they sound just fine.

 

.....X2!... Altough, when it comes to texters, I would prefer a double barreled "horn".