Brake light switch

Simon · 04-22-05, 04:29 AM

I need to rig up a brake light switch now my new brakes are fitted.
Can anyone please post some pictures of their solutions?
Many thanks

Simon

Julian West · 04-22-05, 08:22 AM

How about put a tee in the hydraulic hard lines to the front calipers & then screw in a hydraulic switch. You can get these from most motor factors.

Hope this helps,

Brian Magee · 04-22-05, 09:00 AM

Simon

I have just fitted a mechanical (non hydraulic) one to Tim Martin's car. He should be at Stoneleigh and I am sure he will let you have a look. It is mounted on a bracket in front of the top of the pedal. The pedal holds the switch open until it is pressed.

Brian.

daveg · 04-22-05, 07:14 PM

Pressure brake switches can be installed anywhere on the brake lines, this one is fitted to a tee on the rear lines, you could replace an exsisting tee with a 4way adaptor and not have to cut the brake line. Pressure switches are around £6 from Demon tweeks or most motor factors.

Tommy · 04-23-05, 08:52 AM

You can get a GM switch for about $6 to mount at the pedal.
I can get you a part number if you need it. Did you know the original GT40s that raced at LeMans had a brake light switch on the dash manually operated? It was to fool the Ferrari drivers into thinking they were already on the brakes before a turn.

Phil · 04-23-05, 08:57 PM

Simon
GM has a nice brake light switch that Tommy mentioned, and in the same bracket for the switch is a normally open plunger type switch that can be used to interrupt the wire that feeds your starter solenoid, thus requiring a step on the clutch pedal before starting...just a thought!
Phil

DC · 04-24-05, 02:58 PM

Here's a simple one that Frank Catt uses on his pedal boxes. Its a microswitch detecting the pedal movement. You should be able to rig something up like this, though I do think the hydraulic method is simplest even if you have just finished bleeding your brakes!
If you have a cross or tee to add a hydraulic switch then you can stop too much fluid loss by using a plastic sheet under the master cylinder reservoir cap when you screw it on - it will create a vacuum and limit loss without total draining of the system.

Gary Gibbs · 04-25-05, 09:58 PM

The pressure switches work quite well.

David Tickle · 04-29-05, 09:01 AM

Hi Simon

I used to have a pressure switch, but it wasn't reliable and only came on if the brakes were pressed quite hard, so for town driving it didn't work. I replaced it with a pedal mounted switch (Escort I think) fitted to an easily fabricated bracket.

Regards

Dave Tickle

Lynn · 05-11-05, 11:51 AM

Dave,

I have used the pressure switches and found the opposite to be true. Indeed, when I used one in my hydaulic clutch line as a safety interlock where the engine will not crank without pressure on the clutch pedal, I found that only lightly laying ones foot on the clutch pedal was adequate to engergize the starter solenoid. (But, if you have to put your foot on the pedal, shame on you if you don't disengage the clucth prior to cranking the engine, except in testing situations, of course, where a broom handle works quite nicely ;-) I suppose the source of the switch will make a difference in the pressure required to complete the circuit; I have used NAPA part no. SL134 throughout.

I have another of these switches on the clutch line near the transaxle. This switch or a microswitch, which senses when the transaxle is in neutral, provide a no-load signal to the engine management computer. The only downside I see to their use is the danger of leakage, which doesn't seem to occur too frequently. When they do fail, they almost never cause complete loss of pressure in the line. That said, a mechanically activated switch does completely preclude this possibility.

Lynn