Toot your own horn!

[resq302]

We've all been there... some moron cuts you off and we slam on the horn to let him know.... well whatever you want to call him or say.  Only, now your horn doesn't sound like it used to or sound at all!  Now in Jersey, we have a simple solution for that..... roll down the window, extend hand, raise finger.      For those of you who would like to be safer and get more of a warning out there before someone actually hits your car, I just did a repair to a horn on my charger that was not working.  Being that the factory Spartan horns are riveted together, I decided to drill out the rivets and see what made these horns work.  (But how will you get the halves back together?  I'll get to that later!)Prior to drilling out the rivets, I wanted to make sure I matched the two halves back in the proper indexing so I made a mark on both halves so I knew where they would line up.  It is really a simple design when you think about it but somehow, these things seem to quit working over the years.  Once the rivets are drilled out, you can carefully disassemble the horn.  Inside the horn itself is a metal diaphragm that appears to be made out of a spring steel.  It is not perfectly flat but kind of dome shaped.  Picture a Snapple bottle cap.  It is essentially the same thing with a metal dowel riveted to it that goes down inside a well.  The two halves of the horn are both made up of metal. The one that has the mounting bracket is made of steel with the actual spiral trumpet being made out of aluminum or white metal.  Inside the steel half of the horn is a metal contact similar to a point set up on a distributor.  What I found is that most cases, the metal contacts form rust and no longer make contact which completes the circuit and makes the horn work.  A little sand paper between the contacts cleans them up nicely.  Now that the horn is apart, you can determine what machine screw size you will want to use to hold the two halves of the horn together.  In my case, I purchased six (6) 8-32 machine screws.  While the horn is apart, I finish drilling out the rivets all the way through on the trumpet half side of the horn with a drill size slightly smaller than what the machine screw would be that will be holding it back together.  Once the holes were drilled out, I got out my tap and die set and threaded the holes on the trumpet side of the horn for the 8-32 machine screws.  This step you need to take your time as it is possible to crack the aluminum / white metal trumpet part very easily.  I recommend turning the tap with thread cutting oil and then backing off on the tap occasionally to ease up on the pressure it is exerting while cutting the threads.  Now that the threads are cut, you can reassemble the horn.  I chose to put a dab of medium strength lock tite on threads due to the vibration of the horn, I didn't want the screws coming loose.  Now, to make sure it worked before I painted it back to the satin black color, I hooked it up to a battery booster (if you don't have one you can mount it back on your car) and just touched a jumper wire from the pos. side of the booster pack to the contact on the horn while the mounting bracket was attached to the neg. side of the booster pack.  The horn let out a blast and it was time to apply some paint.  What I did next is optional as I wanted to try and retain a rivet looking appearance.  I took a dremel tool and with a cut of wheel, I cut off the remaining threads on the trumpet side of the horn so they were flush to the horn.  The other side of the horn where the screw head was, I ground down and cut off the head of the screw so it was flat and no visible slots for the screw driver remained, giving it the appearance of a rivet.  Once your paint is applied and dry, you can reinstall your horn and toot with the best of us and have a working warning device!

1st pic - Red arrows show 3 of the 6 rivets on the horn prior to disassembly.
2nd pic - disassembled horn with two halves after external sand blasting

[resq302]

1st pic - red arrow shows where the electrical points are that were rusted and would not allow the horn to work
2nd pic - assembled horn unit with screw heads cut / ground down to resemble rivets.
3rd pic - close up of the cut off screw head.

[terrible one]

Great job and great write-up, thanks for taking the time to share.

[Musicman]

  Good Job 

Thanks for taking the time to post.

[A383Wing]

my horn is broke....

watch for finger!

[resq302]

yeh but some people are blind.  they need a loud noise to scare the crap outta them!   

[Bob T]

yeh but some people are blind.  they need a loud noise to scare the crap outta them!  

You got that right , I've had clowns jog across the road completely oblivious to the world with their ipod wound up on high.

He didnt hear my finger so the Airhorns brought him back to reality, abruptly  


Good how to tip , resq302 

[Charger_Dart]

Nice write up, thanks for doing this. 

[resq302]

One little extra thing I did while it was apart, the steel half of the horn, I took some Evapo-rust on a paper towel and just let it sit on some of the rusted areas and then wiped the rust away.  I figured I had it apart, I might as well to keep it all nice and clean.  I probably could have even used some of that RPM stuff on it hind sight to also prevent the rust from coming back but oh well.  I can do that on the next one!

[440]

Great write up   Will have to take this thread on board.

I have sadly found that horns don't work no matter how loud they are. I've been hit three times by un-attentive drivers in parking lots. All while waiting for someone backing out of a parking spot. Of course your trapped in with nowhere to go so the horn is the last defense. Two required a trip to the body shop and the other I was hit by an illegal while in my 4WD.

[resq302]

One important thing I forgot to mention...... make sure you have the correct mounting bolt.  This bolt has a special washer with something like teeth that will cut through the paint on the horn to give it a good ground.  I got mine the last time from Bill Alphin.  If I remember right, they are a dark olive gray phosphate color.

[bill440rt]

Nice write-up, Brian! 

I tried this once on a Prestolite horn, still couldn't get the damn thing to work again. Cleaned all the contacts, inside, etc. Dead as a doornail.

[tan top]

    nice work !! clever stuff  

wernt there 2  makes of horns  used on our cars ??  i forget now     have one with a bolt holding the bracket on & one with a rivit  thingy like in Brians top  picture  

[resq302]

yes, there was a Spartan make and a Prestolite make.  The ones I have on my car (and spares now) are Spartan.  I have no clue which went on what car or was available at what factory.  Could have also been a thing where they had more than one vendor should they have a production delay for that vendor, it would not hold the assembly line up.

[tan top]

yes, there was a Spartan make and a Prestolite make.  The ones I have on my car (and spares now) are Spartan.  I have no clue which went on what car or was available at what factory.  Could have also been a thing where they had more than one vendor should they have a production delay for that vendor, it would not hold the assembly line up.

      thanks for the  info Brian ! appreciated 

[resq302]

Anytime!     I have not looked closely at a Prestolite version but I would imagine that they all have the same basic principle of how they work.

[ODZKing]

my horn is broke....

watch for finger!

Can you see me now     LOL!