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Discussion Starter #1
I am redoing the brake system on my 1969 Spider Veloce roundtail. LHD, 1750 USA model. Floor mounted master cylinder. There is a Brake pressure differential valve located on the firewall that has been rebuilt. There are 3 electrical switches on the unit, one on top and two pointing forward. The top switch has been obtained (Porsche used this switch also). I am in need of the 2 forward facing switches. These switches have straight threads and use a copper washer. I have contacted IAP, Centerline, and Highwood Alfa, all of which have only switches with tapered “pipe” threads for direct mounting to MC. I believe that this was a one year application for USA cars.
Can anyone help with availability, original part numbers, cross applications, or other advice.
 

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The forward facing two are brake light switches. The should be taper thread, I think. I replaced both in my 69 Spider with parts from Jon Norman, as they both were leaking right through the crimp. Mine went in fine.

Andrew
 

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Looks a lot like this Porsche part, 113-945-515-H-M4, mid 80s and earlier 911s used 2 on an Ate master cyl. try Pelican, Autoatlanta, Automotion etc
Cheers
 

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If it truly has a straight thread with washer, it may have been buggered. One of mine threaded much deeper than the other, that's a risk with pipe threads.
Andrew
 

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If it truly has a straight thread with washer,...
I rebuilt this switch 04 Jan 15 and the brakelight switch fittings, as well as the switches, are 10 x 1.0mm straight thread with sealing washer (10 x 1 switches w/washers were removed). The 2 input and 2 output lines are also 10 x 1.0 straight (with DIN flare) while the single brake failure switch is a 12 x 1.0.mm. All the threads are perfect and need only the correct switches.
The tapered switches will start in the threads but go in only about 1 full turn by hand before starting to bind. Would these tapered switches work? Perhaps. But I could see them most certainly buggering up the threads.
 

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papajam rebuilt the entire unit (not switches for me)..suggest you consider that as well

here's a method for testing the swithches (again, papajam sent this to me):

The two front switches are for the brakelights. These normally open switches will close the contacts when pressure is applied to the hole in the center of the threaded portion. Compressed air I think would be the easiest for a bench test. Connect the 2 ohmmeter leads to the 2 male spade connectors. With no pressure applied to the hole, the meter should read open (or infinity or OL depending on the meter). With pressure, the reading should be pretty close to 0 (zero). These switches are readily available from a number of vendors.
For the failure switch on the top, connect 1 ohmmeter lead to the single male spade connector and the other to the threads. Reading should be open. Push the plastic rod straight up toward the spade connector. Reading should be close to zero. These switches are NOT available (I've spent years looking). A 2 spade connector switch, although not stock, is available though.
 

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Discussion Starter #9
69 brakes

The switches are straight thread, screw in and out smoothly, and the threads are not bunged up. Hope the photos are clear enough to show. Quite possibly Alfa had multiple suppliers for this part. Sure have encountered that before!
 

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I used "Early Beetle" VW 2-prong brake light switches, cheap, plentiful, widely available ~ $6 ea. work great.

VW part No. 113945515H
 

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Discussion Starter #11
69 brakes

Donco, and friends

I googeled that part number and found the switch. I cannot tell from the picture if it is straight threads or tapered. $6 on ebay. I called the local VW-Porsche dealer... not in stock and can order for $58 each. Could not tell me about the threads.

Will shop locally when the snow ends and report results. Thanks everyone for all help.

George
 

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The VW switch is 1/8-27 NPT tapered thread. The Alfa switch is M10x1.0 Iso straight thread. I've had no problem with mine leaking with teflon tape, and it's been many years. The 1/8 NPT thread is .405" o.d. at the fattest end compared to an M10 being .394" o.d. The difference in pitch for such a short engagement is trivial.

If you want to keep matching threads but use a less expensive readily available 1/8 NPT switch, you would need an adapter such as this:

Metric Adapter/Oil Pressure



$11.91 ea., also available on Amazon at similar price from various vendors, part number: BDHZ-2265

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Edit: Alfaholics has the proper Alfa switch for 8 GBP ea.



(approx. $12 US). Shipping shouldn't be much. I've ordered from them before for a set of OE spec springs and as I recall, shipping to US was reasonable.
 
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