They are a little tricky to get to work. I found the rubber under the horn button is pretty stiff so it takes some effort to push, and then it has to travel a ways to hit the horn ring, at least on mine anyway.
I have made a couple of different top bushings since I couldn't find one back when I was building the truck. The first one was made from hard wood, don't remember which kind, but it worked pretty good. I bored the center hole slightly big so it always bothered me that the shaft would move slightly. I am now using a teflon bushing with a needle bearing in the center. The bearing takes most of the load, and the teflon absorbs the bumps and is a insulator. I made it long then cut the horn wire to match. If I really work the steering in a slow parking lot or such, the horn honks every now and then. I leave it alone since it works pretty good most of the time.
Your new bushing should press in pretty tight, they should be about the diameter of the tube before it narrows down. Just press it in till you can see it in the hole of the tube and adjust the horn "S" wire till it works with out honking all the time. Spread the "S" wires so they touch the steering wheel metal as they go through, thats where it gets is ground. I used a deep socket to drive mine in, but then the whole column was out of the truck so I could slide the tube off and on the gear box easily. A piece of pipe should get the job done, just don't bend the brass horn ring /contact. It can be reused on a home made bushing if you are careful in prying it off. I would replace the wire with a good heavy insulated wire if you go to working on it.
Good luck with it. Its not to hard to get working once you figure out how its suppose to work, its just not the best idea they had.
Joe
The whole system works off of ground. You should have a horn relay somewhere. The relay powers the horns, and the horn button supplies the negative side to activate the relay. Its a safety feature so you are not running positive voltage up the steering column. If the wire does get rubbed through, the most that will happen is the horn honks, if it was a positive voltage system, you could get plenty of sparks and maybe a fire.
