mechanical brake light switch mounting question

My brakeline pressure-activated brake light switch doesn't work right so I just bought a mechanical switch to replace it from NAPA. I intended to make a bracket to mount the switch inside the car, to be activated by the brake pedal. But my master cylinder is under the floor and the brake pedal is floor mounted, rather than suspended. So it would be much easier to make a bracket and mount the switch under the car near the master cylinder.
Here's my question: Is it a bad idea to mount this plastic switch under the car, where it may be exposed to the elements and to potential road hazards?
Thanks for your advice.

 

I did as you suggested mounting a plastic switch under the car.

I wrapped the thing in electrical tape and never drove it in the rain.

Just bought a new waterproof on to replace it with. Ron Francis Wiring sells them.
Mine was on back order for about 90 days. Hard to get.

 

I need one of those for my bike. Any other sources?

 

Thanks for the lead, 2many projects,
I just checked the Ron Francis Catalog and found a couple different ones that are designed to do the job.
Francis' plastic one, similar to the NAPA one I got, is described as for use under the dashboard.
I called Ron Francis to check stock status on their waterproof switches and lever type switches, but today's Saturday, and the office was closed. I just checked. American Autowire's catalog lists some too. I don't know the stock status.

 

i have installed a micro switch under the floor of a friends car a couple years ago, no problem yet and he does drive it in the rain.

 

Chev cars,.....until about 1953 used a stoplight sw that mounted to the bottom side of the toeboard....the actuating arm was held in the "open " position, by the brake pedal arm. They seemed to work ok, even during western N.Y. winters,....road salt and all!! I 'm using one on my 40 Ford pickup as a safety sw,...the clutch ped. must be pushed, in order for engine to crank.

4TTRUK

 

I use a good old arm switch from a 40-50's chevy truck, they're meant to be outside the cab. You can get them in normally open, normally closed and reverse arm.

 

Yes, as they are not designed for exterior use.
The best switch I've found is the SW-42 sold by Ron Francis. It is water proof, not just water resistant, and can handle high amperage halolgen bulbs without the need for a relay.

 

Why not just replace the original malfunctioning pressure switch switch? Wouldn't that be less aggravation than installing an manual one, then having a switch in environment it wasn't intended for?

 

i agree with 1oldtimer i use those flip switches on all my cars and have never had a problem with weather or road grime, you can get them at napa auto parts and there cheap

 

I use this brake switch under pedal arm in the engine bay. Same as above only adjustable. Had it there 5yrs now and I drive rain or shine, never an issue.

 

Use the one "Old Timer" sent the pic of.... Works ok under the car.

4TTRUK

 

Thanks for all your suggestions. I picked up a lever type switch looking like the one pictured by mgtstumpy. Ron Francis had it in stock (SW68) for under $30. It took me a while to figure out the best place to mount it on my Model A, but I settled on mounting it to the firewall/floor, a little below where the pedal rod comes through. After some adjustment problems, it worked fine, but occasionally the brake lights stayed on after the brakes were off, due to the pedal not always releasing all the way. This was solved by putting a return spring on the pedal arm. Now the brake lights come on instantly when I touch the pedal, and turn off as soon as my foot's off the brake.
The reason I like this better than a line pressure activated switch is because it's simple, mechanical, responds instantly, and, I'm told, is more reliable.
(My old switch didn't always work because the line pressure was not high enough to activate it unless the brakes were applied very hard. As an alternative,Francis does offer a low pressure switch. The wires from my old pressure switch connected right up to the lever switch.)

 

I believe it's NAPA p/n SL128--at least that's the one I'm using on my '40 mounted to the toe board behind the brake pedal arm.

 

I just picked up the Ron Francis SW-42 switch today. It's normally closed so how would it get wired/mounted? The pedal is floor mounted so would the switch be above the pedal or below the pedal.

 

SL 128 or 129 are similar. I've bought enough the local NAPA store stocks them.

 

All brake light switches I've seen are normally closed. You want to mount it under the floor and position to operate by the lower pedal leg. I made a bracket with a small piece of angle iron to mount my SW-42 on the pedal box, and use a tab on the stock '33-'34 brake pedal to push the button and open the switch when the pedal is returned.

 

I have used those plastic Chevy ones under the floor board of several cars and have yet to have one go out (about 10 years now).

 

you can buy normally open OR normally close switches (from auto parts store or cole hersee) and you can get one with an arm going to the left or right. Which aids on mounting it. I used a normally close one on my '54 panel, on the firewall, arm behind the pedal arm (between firewall and pedal arm).

 

I installed a lever arm switch on the track roadster after the hydraulic switch failed. It's been in service rain or shine without problem for several years now. Mounted it to the underside of the floorboard next to the pedal slot. Rain a new pair of wires down from the dash and never thought about it again. These have to be the most foolproof installs and dependable switches ever. Still in production after about 60 years. That says something.

 

Here's a pic from the Ron Francis catalog showing an example of mounting the SW-42.
Also a sketch I drew of how I mounted the SW-68 lever switch in my car.

 

Hi all - a newby here, but with an urgent question, please - 1OldTimer says (above) "I use a good old arm switch from a 40-50's chevy truck, they're meant to be outside the cab. You can get them in normally open, normally closed and reverse arm."

Can you advise where they can be bought in normally open format (ie with no current being transferred when the switch is at rest)? I have tried a Speedway arm, but it's closed when at rest, so the brake lights are on, until I brake...

Due to the design of the car, I can't take this under the floor, and would like a simple arm for convenience.

Urgent help sought. thanks!

 

Check the Cole Hersey website

 

I used this one under the car because it is waterproof includinging the wiring pigtail.
They will also work inside the car, mounts very easily.




https://www.summitracing.com/parts/...4JC69i63qG5hoC6jLw_wcB&ibanner=MobileSwitchNo

 

Ok...it seems the Cole Hersee website is not as user friendly as it was a couple years back...but here are a couple links to their normally open and normally closed brake switches:

http://www.littelfuse.com/products/...utral-safety-and-backup-switches/8486_05.aspx

http://www.littelfuse.com/products/switches/special-purpose-switches/stoplamp-switches/8486.aspx

Their switches are available through most parts houses (O'reilly's, Napa, etc.)

Good luck

 

Thanks Anothercarguy - I have emailed littelfuse. Also, I am ready to order the alternative, DDDenny, but all other suggestions welcome

 

Thanks!

 

DDDenny posted the one I use on my A. Works great and never had a problem with it!
Ron Francis product.


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I used the same lever switch from Watson Streetworks for 10 years now under my 39


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What he said - 39cdan

Me too, over ten years