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MG Midget and Sprite Technical - Brake Light Switch

The brake lights on my '69 Gan 4 midget only come on at the bottom of the peddle. I can't see any adjustment so is it a case of fitting a new switch, or just living with it.

Thanks

Ian
I Ball

it works on hydraulic pressure so a new switch shouldn't make any difference.
Try bleeding the system and/or adjusting the rears, so the bite point is higher up the pedal stroke.
David Smith

Ian,
There is a lot about failed and sub-standard brake light switches. When mine failed the symptom was that the switch still worked, but needed progressively more brake pedal pressure to get it to come on (because of deteriorating contacts inside the switch) Effectively it meant the pedal having to be pressed further to the floor to get them to work, just as you describe.

Replacement ones lasted less than a year each (quality issue). Solution was to wire the switch via a relay so that it was operating on lower current and not then burning out the contacts.
Guy

David and Guy,
Thanks for the advice,

David, the brakes themselves are fine, very responsive and don't need adjustment.

Guy, Thanks for the heads up on this I'm wondering if fitting a low current high output LED lamp replacement would work instead of using a relay?

If I decide to try a replacement switch, is there much spillage of the brake fluid? I'm assuming that the whole system will need to be bled.

Cheers

Ian
I Ball

I have had to replace brake light switches twice now

Neither time did I have to rebleed the brakes, each time I did it I expected to have to though :)

So plan to but see if you need to afterwards

I didnt even get much of a dribble of fluid out of the threaded union
Bill 1

The other thing to reduce any spillage - which applies to any clutch or brake work - is to remove the filler cap from the reservoir, stretch some polythene or cling-film over the top and replace the cap. seals the lid preventing air from getting in the air hole so the system then doesn't leak fluid out when you slacken of items like the brake pressure switch.

I thought about high output LED lamps but they were more expensive than a simple relay!
Guy

Ian, I think it just luck i've had this with three cars now the last switch works fine

buy new as most of your braking wont be hard and so your brike lights wont light up which drivers behind you will find very annoying

if in less than 12 months the new switch has gone faulty and you'll know sooner than this take it back and get it swapped free of charged

good ones last many, many years

note I'm not a fan of relays unless you really must
N Atkins

For information on making and installing a relay/arc suppression circuit, see the article, Brake Light Relay in the Other Tech Articles section of my web site at: http://homepages.donobi.net/sufuelpumps/ LED brake lights in place of the original incandescent bulbs should eliminate the problem with the wimpy switches sold today (although I wouldn't be entirely surprised if it didn't, considering the flimsy switches that are on the market). Cheers - Dave
David DuBois

I did buy a Kawasaki mechanical brake switch at last.

Flip
Flip Brühl 948 frog 59

The replacement hydraulic brake light switches are, like some flasher units, very poor quality.
After two replacements I fitted a mechanical switch from a Mini - it cost less then £2 and is linked into the relay used to help protect the hydraulic switch (which still failed).
it can be fitted in the exisiting hole in the pedal box - mine required a little filing to get a good fit - see photo.
It lights as soon as the pedal is brushed by your foot and can be adjusted to suit your requirements.


Jeremy 3

This thread was discussed between 14/07/2011 and 16/07/2011

MG Midget and Sprite Technical index

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