MTFCA Forum

My horn would just about spin to make a noise you could hardly hear.. Took it apart, cleaned the armature and established the brushes looked good and made contact. put it back together and restored power to it. It now spins freely but all I hear is the spinning motor and no horn sound. What am I missing.

What is missing is lack of information on WHAT kind of horn you are asking about. Model T's didn't use a motor driven horn. Different horns have different adjustments so need to know before making suggestions. Does it have an adjustment on the diaphragm or?

Mark, the horn is on a 1925 coupe that I just bought. When I took it apart, there is a field coil, an attached armature with brushes. That sounds like and looks like a motor. When power is applied and the horn button is pushed, this "motor" spins. What do you call it if not a motor?

What brand? What you are describing is not a Model T horn. Model T horns used an electromagnet that pull the diaphragm back and forth. Please read my first post, there are different adjustments to make it work/sound depending on what brand it is. I did not say it was not a motor driven horn.

The DC battery horn (motor driven) was introduced around 1920, earlier horns were AC (magneto) a forum search brings up lots of information.

DickC,
Your post describes your horn as motor driven (DC) and not magneto driven (AC)
You have most probably fitted the diaphragm on incorrectly. On the diaphragm on one side there will be an anvil (piece of hard tooth shaped steel) which the motor driven (tooth shaped) wheel strikes and causes the sounding noise.
Rotate the diaphragm until the anvil contacts the armature wheel teeth at right angles (Just have to touch the tip of the teeth) You could find an adjustment screw on the motor case near the commutator.
Screw the adjusting screw in and out for your desired sound....N..


r

US battery horns were never motor driven horns. They still used the electromagnet setup only had points that opened as the diaphragm was pulled by the magnet and closed when it sprung back.

We have established that it is a motor driven horn, so let's help him with that and not with what "should" be there.
Motor driven "Klaxons" make sound by striking a "tit" on the diaphragm, they usually turn a wavy washer on the motor shaft to do this. The diaphragm must have paper gaskets, one each side, to allow it to sound properly. there usually is an adjustment for the motor to strike the diaphragm--on most period horns this is a screw that pushes against the motor shaft, often times the screw goes through the cover to make adjusting easy. On later models, the tit on the diaphragm is threaded and has to be adjusted, usually by using a long socket to reach inside the horn.
Now sometime the adjusting screw actually bears on a ball bearing on the motor shaft for less friction--if you loose that single little ball, you'll have to find another one (bicycle shops used to have these loose).

Sorry I was just trying to find out what brand of aftermarket horn it was to better help him. Poppie and Davids instructions should cover most of them.

Semi Related -

I have a "hand klaxon" that soounds like an anemic duck on it's last leg... I tried adjusting the center nut & screw, but it only proceeded to lock it up. Loosening it so it would run went back at best to the sad sound it almost makes... I'm kind of at a loss, as there doesn't seem to be a middle ground between silence and great-grandma ewe on her last breath...