Brake light switch options?

[Duncan M]

I ran across a picture of the insides of (likely) the TC brake light switch. Interesting how something so cheap can work so well. So I am curious if Moss etc sells a copy of this for $64, or something a little better?

I ran across a similar switch on ebay a few years ago that looked promising. Anyone ever tried one of these? They are from India, and run anywhere from $6 to $40 delivered. Both about the same size. Either a "no name" brand or "Swiss" available. Look using a search on ebay like "royal enfield spring brake light switch" Like here- http://www.ebay.com/itm/ROYAL-ENFIELD-R ... qX&vxp=mtr

[frenchblatter]

Unless yours is physically broken or rusted they work much better than the electric switches. Just clean it up and coat with grease (not the contacts) and it will work for years to come.

[Duncan M]

There was a recent discussion in the email group about ditching the original switch and modifying the brake hydraulics to take on a more modern hydraulic pressure switch. I was not sure if they were serious or not.

Norman mentioned cleaning up the switch and greasing it inside. The switch on my '49 TC has never been touched (since 1952 for sure) except for some light oiling and new wires connected. With low current LED brake lights in now, I imagine the switch contact will last much longer than had I kept tungsten bulbs.

The TA/TB/TC switch looks like the same used on P Types and the J's, while the MMM's used something similar, but with a lever on the side. http://www.triple-mregister.org/forums/ ... hichpage=2

[Norman Golm]

As a truly long lasting solution to the TC brake switch I tapped the fitings at the end of the master cylinder and installed a normal atumotive brake switch. I tapped the fitting with an 1/8" tap. See picture attached

[frenchblatter]

I think that the mechanical switch, properly cleaned up, sealed with a cardboard card and properly adjusted is far more reliable than the hydraulic wsitches.

All modern cars have mechanical switches, pity they're so cheap and nasty.

[SteveW]

The issue with the hydraulic switches tends not to be the component itself, but how its fitted. They are very popular in the kit car community (I put one on mine). The main issue is to ensure that they are not positioned such that they can trap an air bubble between the sensor head and the rest of the hydraulic line, as these are very difficult to bleed out.

BTW I'm now coming out of a winter hibernation doing other things, so look out for more progress reports and questions on my TC restoration. As a quick recap, I had finished the stage 1 wood frame build and had just started stage 2 before I put it to bed for the winter. This will be quite a challenge as some of the compound curves were only rough cut when I got them.

[frenchblatter]

I'm not sure any modern car has an hydraulic brake switch. I changed my hydraulic swith on the Caterham to a modern mechanical one operated by the pedal.

The main differencve is the mechanical switch can be adjusted to operate as soon as the brake pedal is touched whereas you can lightly brake with most hydrauilic switches before they operate.

[SteveW]

you can lightly brake with most hydrauilic switches before they operate.

Lightly brake in a 7 style kit car??? I thought the idea was to have your right foot on the floor, whichever pedal it is using

[frenchblatter]

Steve, Funny you say that. I went to an ex police driving instructor for a days course in defensive driving. When we were finished he was marking a paper and his partner, also a professional drive, saw the paper. He had marked "braking" as problem and I said I would dab the brake pedal if anyone was behind ythen slow through the gears. The two of them had a heated discuscusion as to whether that was OK. In the end he marked it OK and I got 100%. He said I didn't need any tuition and was guilty about taking my cheque.

It was nice to know that I pased this mans test. He had taught the SAS to drive very fast in a Lotus Carlton when they took over driving government cars. They would be driving at 150 mph + along the M50, the emptiest motorway in the UK.

[Steve Simmons]

I have a hydraulic switch on mine as well. The mechanical switches located under the car are subjected to a lot of oil and road grime. I think that's why they don't last as long as one might expect. The hydraulic switch will last for many years since it's sealed. I use a Ron Francis SW-32 low pressure switch. Similar to, and compatible with, MGB switch.

[Franz Tenbrock]

Hello
i don t find the break light swith on my ta
also i don t find a picture in the web where to search for
in the moment i can t get under the car to look for, only looking from the side laying on the floor :-(
when i open the bonnet and look down i can see two springs, one for the brake and one for the clutch
so where is it on my ta,
if it is mechanical switch it should be on the spring??

[Duncan M]

I ended up using the original switch again, after a good cleaning and greasing. Works fine. Franz, on the TC the spring or link is attached directly to the pedal assembly, underneath the car.

[Franz Tenbrock]

Hello
i went to the car this morning, and test the brake switch.
it works
so somewhere should be a switch
don t found it in the moment.
Here a picture from the car, opend bonnet right side
there are two springs
one from the clutch pedal
one from the brake pedal
but no switch
no wire

so i have to search where is this switch

the electric on this car works, but no colour is correct and so on.
in the moment i study the wiring diagramm
i am thinking about buying a dynamator
i would take off the Lucas340 from the cjr3 printed case,
then i will putt 3 relays with fuse in this case
i would take original like new wire with correct colours
and so on

[stephen stierman]

If you run silicone brake fluid, the leaves inside the hydraulic switch tend to tarnish and than require a lot of foot pressure before the brake lights come on. I believe you can find street rod type hydraulic switches that can be used with silicone fluid, just something to keep in mind.

[Steve Simmons]

The type of fluid would have no effect on the switch, since the fluid never touches it. If the car has been converted to a hydraulic switch, it should still have no effect since they are compatible with all common fluids. I have hydraulic switches on three cars (MGA, MGB, MGC) all with silicon fluid and never any issues. The switches so eventually go bad but not from fluid, but rather from electrical arcing damaging the contacts. Modern switches are not as good as the ones we used to get. Installing a relay can help the switch last much longer.

Franz, have you looked on the rear of the master cylinder to see if someone installed a hydraulic switch? Follow the brake lines. Maybe someone added one at a junction fitting.

[Duncan M]

Brake switch arcing can be greatly reduced by using a LED type bulb, which draws much less current.

[Franz Tenbrock]

Hello
no picture found where the original switch should be.
is it in front of the pedal where i made a photo above
and where should be the wire, what way does the wire take to get to the switch.

[cdrolshagen]

Hello Franz,
attached picture you can see where the orignal swith is fitted to the chassis rail,
ther must be two holes in the chassis rail,
cheers Carl

[stephen stierman]

The type of fluid would have no effect on the switch, since the fluid never touches it. If the car has been converted to a hydraulic switch, it should still have no effect since they are compatible with all common fluids. I have hydraulic switches on three cars (MGA, MGB, MGC) all with silicon fluid and never any issues. The switches so eventually go bad but not from fluid, but rather from electrical arcing damaging the contacts. Modern switches are not as good as the ones we used to get. Installing a relay can help the switch last much longer.

Franz, have you looked on the rear of the master cylinder to see if someone installed a hydraulic switch? Follow the brake lines. Maybe someone added one at a junction fitting.

Steve what brand of switch are you using? Maybe that is the issue? Seems they work ok for a couple of years and than it takes a lot of pressure to actuate the brake lights. I did use a grinder to take one apart to see if I could get a look and noted the contacts looked a bit corroded and thought maybe brake fluid was getting by the seal.
Steve

[Steve Simmons]

What I've noticed is that the modern Lucas replacements don't last no matter what type of fluid. The contacts break down and it requires more and more foot pressure to engage. The only cure for that I've found is either a relay or LED lamps as Duncan noted. My TC has LED rear lamps and has been running a modern Lucas replacement for many years without issue. But on my "modern" MGs the switches kept failing after a year or two so I switched them to Ron Francis SW-32 switches. I've only had one failure in about ten years on that type. That was on my MGA so in a pinch I put a Lucas back in and it has been fine ever since, but that car doesn't see a lot of miles so I'm sure that's why.