Installed mechanical brake switch

[jeff1hughes]

Well I found a way to put in a switch easily and inexpensively, if you can believe that with a 911. The switch is a stoplight switch, so it was even designed for the job at hand. I now have brake lights as soon as I touch the pedal - what a concept!

[jester911]

What is the switch from?

[DSouth]

.....and where would one find one of these switches?

[jonbot]

subscribed, I gots ta do this...

[jeff1hughes]

You won't believe it when I tell ya...



49-53 Cadillacs and Chevys ! Old school American iron. I went into NAPA, took there picture book and looked for a normally closed switch that had a bracket on it that looked like it might work. We ordered it up, had it the next day, and I figured where it would work out to actuate on the brake pedal. Two screw and a little bending of the switch shaft and whalla, instant on brake lights.

[TroyGT]

I just replaced the failed pressure brake switch with a mechanical one on my 86 911 and it worked great. I went to NAPA and bought new bulbs and the switch. For anyone else out there interested, the part number is: SL128 or also on the package is M10215. It cost me $16 bucks and they had it in stock. It is a 49-53 Cadillac switch. Like Jeff, I had to tweak the angle on the actuating arm a little in order to get everything coming on and going off appropriately. I also trimmed about an inch off one corner of my rotting wooden floorboard to allow proper clearance. The unit is very small and tucks nicely under the gas pedal... looks just like the pictures Jeff included.

Cheers.

-Troy

[porschenut]

Great! Do you have a picture of the unit before it's installed? I'm staring at your picture trying to figure out what actuates the switch. Does the brake pedal release the arm somehow?

[Gemballa2006]

Would love to do this, any chance of someone doing a tutorial on this one with photos.

[Danny_Ocean]

Originally Posted by porschenut

Great! Do you have a picture of the unit before it's installed? I'm staring at your picture trying to figure out what actuates the switch. Does the brake pedal release the arm somehow?

Bump. Also interested in seeing a straight-on shot as to how the lever is actuated.

[jeff1hughes]

When I get my car out of storage (not for a while now - just got 10" of more white stuff here!), I will be happy to take more pictures. If my memory serves correctly, the shaft knuckle moves the switch I think. I could be way off though, I haven't looked at it since I did the job.

[Danny_Ocean]

That would be great. My car isn't going anywhere, either as it's sitting on the lift, gutted. Bought the switch today.

[RWebb]

some pics here that might help

Yet Another Boring Rgruppe Car – Part II, Suspension

[Danny_Ocean]

Originally Posted by RWebb

some pics here that might help

Yet Another Boring Rgruppe Car – Part II, Suspension

I see pics of the pedal cluster, but can't see how the lever of this switch is activated. The lever has to travel in a significant arc to activate.

[Mitch Leland]

Now what about the cruise control... To disengage the C/C you have to really jam on the brakes so I usually do it from the stalk on the steering column just for that reason.

Some time back one of our members did a post using a mechanical switch just like this post for the C.C.

I bought new hydraulic switches in hopes of improving the reaction time to the brakes and C/C, but have never installed them. Are new hydraulic switches a lost cause?

[Koizumi]

Sorry for bumping an old thread here but I am curious as to how to connect the Cadillac switch into the brake wiring. I've got the switch here sitting on my desk, but I am not sure how to wire it up. Any pointers would be greatly appreciated

[911pcars]

Originally Posted by jeff1hughes

Well I found a way to put in a switch easily and inexpensively, if you can believe that with a 911. The switch is a stoplight switch, so it was even designed for the job at hand. I now have brake lights as soon as I touch the pedal - what a concept!

Good, or welcome to the 60's, early 70's when the pedal assembly included a mechanical switch. BTW, maybe I missed it, but a slotted arm or threaded stop light switch would provide a way to adjust closing the brake light circuit when the brakes are applied.

Sherwood

[Koizumi]

Where/what are those wires connected into?

[john walker's workshop]

well i own and have owned several 49 cads and that isn't one. they are hydraulic pressure switches. that possibly could be a neutral safety switch.

[Koizumi]

Interesting. All I know is that I ordered Napa Auto part # SL128 as mentioned earlier in this thread. Seems well made and very adaptable to SC/Carrera applications. I'm
Just not sure how to wire it up. I'm a mechanical guy but I'm pretty dumb when it comes to electrical

[1-ev.com]

Have anyone tried to install magnet based or Hall effect?

that would be perfect, unless you keep spare credit card near