dan1495

I need to remove the alarm horn from my 72 to have it rebuilt. I have searched the archives but couldn't find a definitive answer to my question - does the drivers side muffler have to be removed to gain access to it or is there another way to unbolt it, such as through the right rear wheel well?

Thanks in advance for any advice.

Easy Mike

You may not have to remove the muffler, but you will have to be able to move it enough for access to the horn.

wrwillcox

On my 75, I could not reach the alarm horn with the OEM round style muffler in place. When I replaced the mufflers, I took the opportunity to remove the alarm horn and clean up the connections. On a side note, I now have the smaller hide-away mufflers and there is enough room to get one arm up to the alarm horn and with some effort, I think you could feel your way to the bolt and remove it. Good luck.

Tooch1

Hi Dan,
Yes, it's a lot easier if you can move the muffler over a little. Just remove your tip from the muffler if you can. That should help. I would also suggest spraying some LPS or PB blaster on the bolt if it has never been removed. Just be careful the spray doesn't get in your eyes when your lying under the car spraying up. Also use caution pulling the wire off the horn as to not break the connector if heavily rusted.
Just a suggestion before sending out your horn. Spray some LPS on the small adjusting screw on the back of the horn. Let it soak awhile. Then carefully try to turn the adjuster, use small vice grips. Once loose, turn it all the way in then out, not completely out though. Get two wires and connect to a twelve volt supply. Negative to the horn mounting bracket after it is cleaned of all rust, and the positive to the horn wire connector after you've cleaned it. See if the horn tries to blow. If you get a thud sound try adjusting the screw in various positions to see if you get it to sound. If you get nothing then it will need taken apart. To check continuity and clean the contact pts.
I've included some pictures below to show the different horn parts. It's not easy, but it is a fun project to work on and restore the horn.
Regards,
Jimmy

Tooch1

Restored horn, that only needed the adjusting screw pictured above loosened and then adjusted to get the proper horn note. This one was media blasted and then repainted. Which I did not do. The guy could not get the horn to sound, so I bought it cheap and luckily got it working with the screw. I keep it as a spare. My original on the car , I did need to take apart and fix.
Regards,
Jimmy

Tooch1

Horn wire connector. Be careful not to break this off when trying to remove your wire. Especially if it has never been removed in over 40+ years.

Tooch1

What the horn parts look like disassembled. The horn is just like an electro magnet. It has a coil of wire connected to a set of points. The electric charge travels through the wires and causes points to react which cause the center plate to vibrate making the horn sound. If the wire coil is not broken anywhere and you have continuity you can more than likely if your lucky get the horn to work by cleaning the points contacts. All the rust needs cleaned from all parts, and you'll also need to remake the gasket that goes between the two parts of the horn.
The original rivets holding the horns together are not designed to be removed, they need ground off on the bottom and punched back through.
A lot involved in this, and probably more than you ever wanted to know. That's why most guys send them away. But I enjoyed the challenge.
Keep in mind that the alarm horns are not dated. They only have a 3,digit number like the one above 939. Some might have 936? So, that being said, what you may be paying to have it restored may be more than finding one that works on line. Even if you are having the car judged, the best a judge can see is if the horn is there, it's overall condition and if the original rivets have been removed and replaced by something different. Just a thought.

Tooch1

Alarm horn parts.
Note: I was not able to get this horn to work. The wire was broken somewhere in the wrap. No continuity.
Regards,
Jimmy

dan1495

Jimmy,

Thank you very much for the detailed pictures and explanations, they will help a lot. It definitely motivates me to get to work on it.

Alan 71

Hi Jimmy,
Nice pictures on the horn!!
Is one side (with the trumpet) plastic and the side with the bracket steel? The rust situations makes it appear that way.
Regards,
Alan

Tooch1

Hi Alan,
Sorry I took so long to respond. My wife and I just got back late yesterday from an 8 day Pacific NW cruise. The top section of the horns are pot metal not plastic. In the photos above of the three parts the bottom is the underside of the top section of the horn.
Regards,
Jimmy

gmfn86

Great information!! ... I'm working on my 72 alarm too. Have it working now but when it's engaged the horn is just making a flashing clicking noise. No horn. I'm going to take the horn out and try your advice. Curious, what size wrench is needed on the one bolt to take it off? If I can't get it to work I'll look to buy one if I can find one on this site. Or, someone to fix it.

Tooch1

Hi,
Great to hear you are going to work on the horn yourself. I'm not positive it's been awhile but the bolt should either be a 1/2 or 9/16 inch. As I stated above, before you take it apart loosen the adjusting screw and try turning it one way or another to see if the horn starts sounding. If you do grind off and remove the rivets here are the 'Socket Head' screws I bought in Lowes. I used the size pictured, but I've been told that 8x32 size head is a bit smaller and looks more like the original rivet once you fill in the hole in the head and paint it satin black. These work perfectly to put the horn back together because the original rivets are no longer usable. Let me know how things work out.
BTW- if you don't get it to work find a working used one on this site, or they are always on eBay.
Tooch

BLUE1972

great pictures, thanks. I just rebuilt mine also.

I used Allen screws and ground the ribs off the outside of the bolts. Filled the Allen with JB weld.

I also rebuilt the switch - the back was missing - electrical part.

I made the rear plate out of nylon. ( what is white when you see them in the pictures)
I used brass rivets (ace hardware) to hold the "arms" on the back nylon. They also acted as the contacts.
I used hobby store brass to make the part of the switch that turns inside the key switch.
I used the spring from a small mag light to push the part that turns against the rivets.
Then JB welded it together as I was afraid that the nylon wouldn't stay in the switch and I was afraid it would pop out as the original did. I did not want to squeeze the metal.

It works- I only made one mistake - I used brass to make the electrical arms of the switch (where the wires attach) - they should be metal.. I'll paint them I guess.

I should have taken pictures.. didn't think anyone would be re-building the alarm..

gmfn86

Good info. You could turn that into a business. There are outrageous prices (I know because I paid them) on ebay for the switches themselves. They are hard to find and year/letter specific to your car ("D" for 72 & 76).

gmfn86

It ended up being a 1/2 socket that fits but as of now I'm having a hard time removing the bolt. I sprayed WD-40 on it and let it sit overnight. I'll try again today. I'll see what I have after I remove the alarm. Again, great info that you supplied ... thanks!!

jeffstuarts

I recently removed the alarm horn from my '69 and used a good Kroil penetrating oil and sprayed it from the wheel well side so I was spraying the threads that protruded through the mounting plate. I have gotten 3 different horns that appeared dead to work perfectly. Unless the coil wire is broken or the corrosion has destroyed the metal inside, there is no reason that you can't get any horn to work.
Jeff

gmfn86

I'll try that angle. I think I've soaked the area pretty good but I'll try a different angle too. I'll leave it go until tomorrow to try removing it again. Been doing other things on the car ... there's always something. Thanks for your advice!

jeffstuarts

If you are going to use WD40 and that bolt is really in there, I think you will be disappointed. In my opinion, you need a high quality penetrating oil. I have found that Kroil is the best commercially available one out there. Some have suggested that a 50/50 mix of ATF and lacquer thinner works well but I have not tried it. Keep is posted.
Jeff

gmfn86

Okay, here goes, I bought and used the spray Kroil product you mentioned and I was finally able to loosen that bolt. Even before getting the bolt loosened and alarm off, the alarm started working with the switch turned, but only for a short period of time. I'm thinking the lubricants that I sprayed on it were helping that.

After getting it off, I was able to turn the adjustment **** as Jimmy suggested and seemed to find the soft spot that I needed. Unfortunately, I may have let the alarm sound too long and get too hot as now I can't get it to work at all, no matter what I try. I may have burnt it out.

At this point and after seeing the work ahead to get the alarm apart and working again ... I think it may be wise for me to either have this one rebuilt by someone knowledgeable at this, or buy a used working alarm. Anyone know anybody who has one for sale? ... or, a reliable individual to rebuild mine? Let me know, please. Thanks!