Horn Button Wire Screw Size

[Bugalooshrimp]

Hello All,

The screw for the wire on the horn button for my 56 is missing. I have searched the forum to get info on the specs so that I could get one, but I am having no luck. Please post if you know the specs.

Thanks,

[JorgeDavidson]

The small bronze one in the center?

I took this pic as a reference; as I can see it´s missing too.
Just looking for someone that can hold the wire w/o peeping out too much the head off; it´s not a hard job.
Jorge
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1957 Oval Window - Polar Silver L324
2008 VW Suran Trendline

[johnshenry]

Its an M2.5 I believe. PM me if you don't find an answer, I can measure one for you...
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John Henry

'57 Deluxe
'56 Single Cab

[Bugalooshrimp]

Hey Jorge,

Good picture. The center hole is actually where the wire goes. The screw is there on the side.

Thanks,

Carlos

[johnshenry]

Ok, I checked, its an M2.5 with a .45 pitch. Normally a "grub" type screw with no head, just a slot. However in a pinch, there are a few other M2.5s in early VWs that can be used. Here is a table of all of the electrical HW specs (sorry for the un-formatting):

Location Shank (mm) Length (mm) Head (all slotted)

Dome light (early split, '51) 3 5 Pan
Gauge illumination lights 2.5 5 Cheese
Oil and gen warning lights 2.5 5 Cheese
Split dash pod headlight switch 3.5 6 Pan
Split dash pod wiper/interior light switch 3.5 6 Pan
Split dash pod ignition switch 3.5 6 Pan
Wiper motor, 6volt, non-parking 3 5 Cheese
Oil pressure switch (sender) 4 5 Cheese
Late oval SWF flasher 3.5 6 Pan
Headlight socket, early bayonet base 4 8 Cheese
Starter Solenoid 5 8 Cheese .8 pitch
Wiper base set screw 4.5 4 Set screw .75 pitch
"D" Regulator 4 6 Cheese
Taillights, '55-'61 4 8 Cheese
Headlight switch Oct '52-'57 3.5 6 Pan


So the screws on the backs of the dash bulbholders can also be used if needed.

I buy all my metric HW at mcmaster.com, they have that size, but you have to buy 100 of them....
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John Henry

'57 Deluxe
'56 Single Cab

[Bugalooshrimp]

John,

That is excellent! I'm going to put your list in an Excel list for future reference . I may just have to buy 100. Hey, what is a cheese head? I have never heard of it. Thanks for your help.

Regards,

Carlos

[johnshenry]

Cheese head is a round head that is pretty much like a very short cylinder, like a round "cheese". Pan head is also round, but the top part is beveled inward.

Go to mcmaster.com, they have pictures and drawings of everything.

I used to buy HW from them, and put together little "service" packs of 10 each of the 7 or so types of screws that are in that list, and sell them at zarwerks.com. But recently I have had to scale down to preserve my time and sanity, and I quit doing those small, inexpensive products.
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John Henry

'57 Deluxe
'56 Single Cab

[Bugalooshrimp]

Thanks for all of the good info John.

Regards,

Carlos

[Splitdog]

John, what is the screw size for split rear-view mirror? I'm having a tough time finding one that small with a large enough head. (no jokes, please)
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CH³NO²

Z = z² + C

Der Blitzkrieg Kafers

#notacallooker

[johnshenry]

[Splitdog]

Right on.
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CH³NO²

Z = z² + C

Der Blitzkrieg Kafers

#notacallooker

[FrankRam]

My horn just stopped working so when I took off the button, it's exactly like the above picture. It seems I'm missing the screw or it wore out. I understand it holds a wire. What wire? What else am I missing for contact? ?

[Brezelwerks]

[FrankRam]

Does the screw itself need to make contact with the round plate? Or is it strictly to hold the wire? I miss the beep as it was working fine. Anyone?
Thanks
Frank

[johnshenry]

Not the screw, but the rivet at the top of the barrel if you look at the other side. This rivet must touch the brass disk when the button is pressed.
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John Henry

'57 Deluxe
'56 Single Cab

[Splitdog]

[FrankRam]

Wish there was a picture of this rivet. The brass disc bulges out in the middle and touches to the screw area where the wire is connected on the other side. Other than that I don't see anything.

[Brezelwerks]

[johnshenry]

The brush in the steering column does not provide a path to ground. It is a path between the negative terminal on the horn to the button, not chassis ground. This circuit is very often misunderstood. The steering column itself is grounded, to check the ground path, ohm out chassis ground to the bare metal inside the steering wheel cavity where the horn button sits. The path to chassis ground is via the steering shaft and steering box.

The horn is switched on its ground side, not its positive side and as such is not "grounded" unless the button is pressed.

Also, make sure there is bare metal in the steering wheel cavity where the horn button sits, where the spring coil wire sits just outside of the button housing. Very often, people paint steering wheels completely and over look this, and the horn won't work.

Diagram of the split/oval horn circuit:

There is an article on horn wiring at my site thebugshop.org, in the tech help section.
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John Henry

'57 Deluxe
'56 Single Cab

[61karmann]

anyone know this screw size intended for the 82mm horn buttons in petri wheels? I believe the screw size is a little bigger as m2.5 is too small..
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