The Triumph Dolomite Club - Discussion Forum

My Dolomite 1300 suffered from a melted brake light switch a few months ago and now my sprint auto also suffered from a failed brake light switch.
as they seem cheap plastic things, I was wondering if anyone had fitted a pressure switch into the brake line.

any comments or thought would be welcome.

Malcolm

There are plenty of decent (pedal) switches about, just not sold as Triumph.
Have a trawl though ebay, you should find an OEM one that is similar, they were used on nissan and many others, you just need one with the threaded section, and possibly to get appropriate nuts!

Using a hydraulic switch will be the same issues as you have at present. Is it decent quality, or not. Perfectly do-able, but you need to find a quality item. (that means avoiding anything branded as Lucas, who don't actually exist any more)

I think its quite unusual to have enough current running for a long time through a Dolomite brake light switch to actually melt the plastic unless something downstream is sucking a lot of current. Do you have extra halogen brake lights for instance ? Or is there a caravan / trailer in use ?
However the Lotus part is the same and last time I used one it was genuine Lucas.

https://www.sjsportscars.com/parts-and- ... ponent=158

I used to have a brake-line pressure switch on my standard 18GA MGB years ago. I was never very keen on it as there was always oil mist on it. And it needs porting into the brake lines to work in an aftermarket application.
HTH,
Tony.

Are these switches not common to most BL cars of the time?

Anyhow, there are alternatives available from the kit car suppliers.




Ian.

PS I use a relay for the brake lights.

The hydraulic pressure switches that are available currently are of very poor quality. On the MG boards I read, many people moan about them only lasting a few months before packing up. You are better off sticking with a mechanical switch in my opinion.

So a switch that is possibly 40+ years old has failed so you want to upgrade to something else, why not just fit another cheap plastic £10 switch (that most other BL cars have had for 40 years) that might just last another 40 years?

Thanks for all the thoughts and suggestions.

my other reason for upgrading to a pressure switch was accessibility, if a pressure switch fails it is easy to unscrew, a small bleed of the brakes and it is up and running but I can't get to the nut on my current brake light switch and it seems that I have to remove a lot of stuff just to get to it.

My 1300 was easy in some way, but the sprint seems more difficult.

Malcolm

Magenta Auto Sprint wrote: ↑Thu Nov 16, 2017 7:58 am Thanks for all the thoughts and suggestions.

my other reason for upgrading to a pressure switch was accessibility, if a pressure switch fails it is easy to unscrew, a small bleed of the brakes and it is up and running but I can't get to the nut on my current brake light switch and it seems that I have to remove a lot of stuff just to get to it.

My 1300 was easy in some way, but the sprint seems more difficult.

Malcolm

Shouldn't be anymore difficult to get at than the 1300 switch, the back edge of the lower dash is shaped slightly differently but I can't see it being difficult and it will certainly be a lot easier than bleeding brakes.

When I have changed a hydraulic brake light switch in the past I have never had to bleed the brakes. Just unscrew one and screw in the new one. No fluid is lost and no air is introduced. But, as I said earlier, if you buy a new hydraulic switch these days there is a high liklihood that it will fail within a relatively short time period. Someone on the MG board took one apart and apparently the contacts are puny. Arcing caused by the brake bulbs (a 3 + amp load) burns them quickly. Put a relay in the circuit and they will possibly last much longer.