Brake light switch mounting

[packtim]

Can anybody make any suggestions about how to mount the brake light switch in the pedal box? We are using a bottom mount pedal box. The guy who was supposed to be designing it has done nothing towards it, and we have to have all CAD done by next week, so it looks like we will be buying one in(looking at Tilton engineering 3 pedal system). Im trying to find the best way to mount a brake light swith on this.Currently im thinking of mounting it on the chassis above the brake pedal, and having a microswitch that will complete the brake light circuit when the pedal is pressed forward.

Any suggestions??


Thanks

Tim

[BryanH]

Use a hydraulic brake light switch from a pommie car. They have 1/8" bspt thread and you can even save on wire by fitting it in the rear caliper banjo bolt.

[Cement Legs]

We use one banjo bolt pressure switch in front and one in the rear so even if one master cylinder were to fail our light would still shine.

[packtim]

Originally posted by Cement Legs:
We use one banjo bolt pressure switch in front and one in the rear so even if one master cylinder were to fail our light would still shine.

Ive heard people talk on these banjo bolt switches, but i cant seem to understand how they work. do you simply connect one end to the master cylinder and the other end to the brake line?How can it tell when the driver is braking? If it seems this simple can you suggest anywhere I can pick them up?

Thanks for your help.


Tim

[mtg]

You can design a pedal base in a week if you really need to. It probably won't be the lightest or most trick one at competition, but the cost of buying one from Tilton has to be astronomical. I designed one in about 3 days a couple years ago in a pinch.

[Mike Cook]

Two things:

1) Pressure switches are the easy way out and add compliance to the system.
2) A mechaincal switch is better. I would suggest designing it so that when the pedal is not being depressed the switch is being depressed. This way you don't need a long throw switch or anything weird.

On a side note. Don't mount your brake light where it is going to get wrecked by your push pull bar.

[Cement Legs]

Your brake fluid travels through the switch. When there is an increase in pressure in completes the circuit... assuming you have connected the wires http://fsae.com/groupee_common/emoticons/icon_biggrin.gif


Originally posted by packtim:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Cement Legs:
We use one banjo bolt pressure switch in front and one in the rear so even if one master cylinder were to fail our light would still shine.

Ive heard people talk on these banjo bolt switches, but i cant seem to understand how they work. do you simply connect one end to the master cylinder and the other end to the brake line?How can it tell when the driver is braking? If it seems this simple can you suggest anywhere I can pick them up?

Thanks for your help.


Tim </div></BLOCKQUOTE>

[Perry Harrington]

On the 79-93 Mustang, Ford used a mechanical BOO switch attached to the brake pedal lever. The pedal has a slightly eccentric hole which allows the booster drive pin to move slightly. The BOO is then mounted so that when the pin moves in the eccentric, the pedal arm depresses the switch.

--Perry

[packtim]

Originally posted by mtg:
You can design a pedal base in a week if you really need to. It probably won't be the lightest or most trick one at competition, but the cost of buying one from Tilton has to be astronomical. I designed one in about 3 days a couple years ago in a pinch.

I know.The problem is is the systems part of the car is broken down into individuals taking car of different parts. Some guy is supposed to be designing the pedal box, and CAD'ing it by Friday. Thing is he keeps missing meetings and generally doesnt do any work. So looks like we are going to be buying it in. I know what you mean though!

[mtg]

Originally posted by packtim:
I know.The problem is is the systems part of the car is broken down into individuals taking car of different parts. Some guy is supposed to be designing the pedal box, and CAD'ing it by Friday. Thing is he keeps missing meetings and generally doesnt do any work. So looks like we are going to be buying it in. I know what you mean though!

That's exactly why I ended up designing one in a pinch. The guy that was responsible didn't pull through, and I was the Chief Engineer, we needed a pedal base, etc.

[Ehsan]

When time is tight, taking "inspiration" from other team's designs is definitely a way to go. There are enough pictures floating around online to get you a good starting point (google images anyone?....). Then you just have to do some minor calculations to pick dimensions and thicknesses. Or you can just oversize it if you are that short on time

Not to mention that it'll probably flatter whoever's design you are basing it on. Still would be cheaper than the Tilton.

[james17]

http://store.summitracing.com/default.asp?Ntt=Brake+Swi...target=egnsearch.asp (http://store.summitracing.com/default.asp?Ntt=Brake+Switch&Ntk=KeywordSearch&DDS=1&searchinresults=false&N=0&target=egnsearch.asp)

(Dont let out my secret, but if you need it summitracing.com has it, and can get it to you very quick. Even if it is heavy you can modify it to make it lighter, and our brake system last year used a pressure switch which was compliant, the car stopped and the brake lights lit up)