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TR2/3/3A Remote brake light switch

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Hamish Racing

Hamish Racing

Jedi Knight
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I have had to replace the pressure switch a couple of times on my 3a but they don’t seem to last. Whilst you can change them without bleeding the system it’s a pain to do with it tucked up behind the wheel in amongst the chassis.
So ready for the next time I have fitted a reasonably robust metal switch to operate off the top pedal/master cylinder cheap part off eBay. A popular modification in the uk.
 

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Were you using DOT5? I think the general consensus is the original brake switches work better with DOT3, at least I remember our esteemed guru Randall thinking that.
 
David that’s a proper engineering solution :smile:
Mrv8q (sorry don’t know your name) no I haven’t moved to silicone. I think it’s Dot 4.
I think that my competition runs put added stress pressure on the original switches. With my sticky tyres I can stand on the brakes with little locking up. This must increase fluid pressures a lot more than ordinary road use.
Like at Shelsely I’m approaching the esses at about 65mph ( it’s very steep ?) and brake hard for the sharp left hander.

Feel free to subscribe as the videos are just for fun and nearly always car related.
 
Problems with hydraulic brake-light switches seem to be endemic in many kinds of cars. I had an MGTD for a while; they were reputed to go though brake-light switches regularly also. DOT5 fluid may be part of the problem, but the fact that they are cheap switches cutting high DC current has to be part of it, too. When I restored the electrical system, I included a relay for the brake lights. Installing a mechanical switch on that car would have been complicated.
 
Thank you. That is my third attempt at a mechanical switch. The first one was a cheap switch from one of the local parts stores and the second one was an expensive industrial switch that I found out later was for AC not DC. This is a switch one of the European TR guys used. I think it is used in a BMW.
Found it on E bay.
Using DOT 5 and never connected my original pressure switch.
David
 
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