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MG Midget and Sprite Technical - Brake Lights

What do people do with their hydraulic brake switches? I would much prefer my brake lights to operate nearer the top of the pedal rather than at the bottom and was thinking of fitting a mechanical switch onto the pedal arm itself.

Any thoughts?

I Ball

Not sure what you mean "what do people do?"

My lights come on before the brakes bite, and mines a hydraulic switch.

Maybe your switch is faulty, or you may have air in the system?

Wasn't there a discussion about bad new hydraulic switches not so long ago?
Lawrence Slater

I rarely just press the brake pedal. Usually, and I think now almost involuntarily, I "dab" the pedal momentarily before then applying the brakes. Comes from years of driving old bangers when one needed the extra confidence that there was still something connected to the brake pedal. But nowadays its more about waking up the driver behind!
Guy W


The brakes are bled and work fine, they've even been bled at the switch to ensure that there's no air lurking in the union.

New front calipers and rear slaves about 5000 miles ago so I'm happy that all is well there.

I know that there was something in MASCOT a few years ago about the vagaries of these switches.

There is something in the archives but I was wondering what others did.

I fitted the current switch about 18 months (6000 miles) ago and it's always been long on the pedal. Perhaps I should try a new one to see if it's any different.


I Ball

Dabbing the pedal wouldn't be sufficient to illuminate the lights, although it would stop me!!

I think that if the brakes weren't so good then this wouldn't bee a problem.

I'll be driving past Mosses later today, I may just call in and have a chat with the guys there.

I Ball

The issue is - or rather was, - that the replacement aftermarket switches are not as well made as the originals. They work OK at first, but don't last. They cannot take the current, the terminals degrade and they then get slower and slower to make the circuit. Eventually they pack up.

I replaced an original switch (failed after 35 years) with a new one that lasted about 1 year. After changing that one twice more, with the same short life span I added a relay so that the switch now doesn't take the full brake lighting current. Its been fine since.
Guy W

in answer to your question, "what do people do?",

either replace your bad switch, and add a relay, like Guy described


exchange the hydraulic switch for a mechanical one (see if there is a threaded hole in the frame of your pedal box, just in front of the brake lever, in the engine compartment)

Norm Kerr

2 x 25W lamps at 12V, is only just over 4amps. (4.16). Geez, they must be crap if the new ones can't handle that.
Lawrence Slater

I dismantled one when it failed. The contacts had a build up of deposit on them which was impeding current flow. Presumably the metal used to make the contacts themselves included the contaminants.
Guy W

2 x 21w bulbs is only 3.5 amps ;o)
Dave O'Neill2

Yup 21 watt. So long since I changed one, I've forgotten the size. Mine must all be old originals to have lasted so long.

So the new switches are even crappier than I surmised then. Does nobody sell decent ones? Are even the branded lucas switches crap these days?

Lawrence Slater

When the switch on my brother's B failed, I sourced a used original for it.

I have a NOS switch in the garage, but it's a screw terminal type, so ideal for a Frogeye or MGA. Alternatively, I may just keep it as a spare and add a couple of flyleads to it if I need to use it.
Dave O'Neill2

this subject has come up recently before, the switches were very hit and miss, slow to react and/or don't last long, I've had the problem on my current midget and a previous classic but the last one I (snatch) fitted 3 years ago works fine so I was either lucky or that supplier had got through the bad stock
Nigel Atkins

I wouldn't go to a mechanical switch as in the 3 years I owned my 1979 midget it went through three switches so they don't seem any more robust! I think a relay would be the way to go. I have not had a problem with MG's hydraulic switches causing any delay. I think yours is probably faulty. The one on my MGB only needs a very small press on the pedal to operate the brake light.

I installed a generic mechanical switch in the footwell. It has been working well for 5+ years with no relay. I was making a custom harness at the time and this seemed like the easiest solution.
Trevor Jessie

before my Midget I had a Triumph that used a plastic switch at the the pedal arm and the new made ones of those used to spring themselves apart and the first you'd know about it was when you saw the plastic cover or spring on the driver's footwell floor

a couple of years previous to that when about 8 years ago) I had a daily drive Rover P6 that was the other classic that I had problems getting a good hydraulic switch for, in the end I think I got a NOS one to work and continue working

most classic owners want cheap parts so that's what we get even if we're not among those tight-fisted owners
Nigel Atkins

I used something similar to this:
Trevor Jessie


I used a mechanical one from a Mini which I think cost about 1.99. It fits in the hole to which Norm refers; this also gives you scope for adjustment. I need only brush the pedal before the lights illuminate and I too added a relay as a backup. No problems five years on.
Somewhere in the Archives there is a picture of the fitting but unfortunately it's not on this laptop!

Jeremy 3

Thanks for all of your answers, it gives me something to think about if nothing else.

I Ball

On my Mk2 I replaced the stop bolt with a regular mechanical brake switch, like so:


This image might be a bit better.



If you wish to sell your NOS switch then I would be interested. Let me know Bob
Bob Beaumont


Sorry, I've only just remembered this thread!

daveo138 AT yahoo co uk
Dave O'Neill2

L. Ball - The mechanical switches are no better than the hydraulic switches (I had a mechanical switch in our MGB that lasted all of two weeks). There is a heavy duty hydraulic switch available that does better than the ones on the market today, but it is quite expensive. The P/N is SW 32 and is available from Ron Francis Wiring The alternative is to add a relay to the circuit as others have done. For information on making up a relay/arc suppression circuit, see the article, Brake Light Relay in the Other Tech Articles section of my Homepage at: Cheers - Dave
David DuBois

I have used mechanical switches, but with a relay. Then they seem to last.
Mike Howlett

I recall making an L braket out of sheet metal on the steering column hanging a spring to thebrake pedel return spring hole and installing a honda motorcycle rear brake switch. Worked perfectly!<yp=AllFixedPriceItemTypes&var=sbar

Steven Devine

This thread was discussed between 23/05/2013 and 25/06/2013

MG Midget and Sprite Technical index

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