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hydraulic brake light switch query
nick205 - 15/3/07 at 07:09 PM

I've got a hydraulic brake light switch fitted in the rear brake circuit, but it seems to take a lot of peddle travel to get it to operate. Had a couple of people get far too close on the way to and from SVA, but it wasn't picked up during the SVA as a problem.

Would it work better in one of the front barke circuits?

Any experience?


graememk - 15/3/07 at 07:18 PM

mines on the front and works ok, leave it in and but another and fit it, then you have a spare lol.


chriscook - 15/3/07 at 07:25 PM

They have a fair reputation of being pants. I used a microswitch on my pedal and it works fine. I know several people who have gone from using an hydraulic switch to a microswitch too and they now have now problems.

If i were you I'd wire in a microswitch in parallel.

Chris


Guinness - 15/3/07 at 07:29 PM

It's quite a common problem Nick!

Firstly the switches are designed to operate within a given pressure range, and as you are discovering it doesn't take much effort to stop an Indy. (I'm assuming you ditched the servo!) See if you can find a switch that operates at a lower pressure.

Secondly, you're brake lights are much lower than most other road users. My wife nearly wrote the Indy off once when she was following me! Think about fitting a third high level brake light.

Thirdly, consider wiring in a microswitch into the pedal box as well, so that even light pressure on the pedal gets the lights to come on. I could be wrong but I think my Audi had 2 things that made the lights come on.

We've had it on trackdays and blats, where someone's brake lights haven't come on and people have got a little close. When we checked they do work, they just need a bit more effort to come on than we'd like!

Cheers

Mike


nick205 - 15/3/07 at 07:43 PM

Excellent feedback chaps

Can you recomend a suitable microswitch?

I did keep the one off the donor brake pedal, but then ditched it in a clear out.


tks - 15/3/07 at 09:23 PM

in the front circuit the pressure is higher sow it will trigger faster..

allot faster as in the rear!!

thats all....

its dangerous!!

microswitch is a good after solution

Tks


chriscook - 15/3/07 at 10:25 PM

I used the lever style from maplin


procomp - 16/3/07 at 08:43 AM

Hi most problems with hydrualic switches are where there is air still inside the switch.

Try mounting the switch upside down and giving it a few genttle taps to move the air out of the switch and into the main line and re bleed the rear system.

Never had any problems with them except when they do eventualy pack up for good.

cheers matt


Hellfire - 16/3/07 at 09:27 AM

Ours is in the rear line and works great!

As procomp said - most of the trouble is due to air. Mount it sideways or upside down to rid the switch of air.

Alternatively - leave the switch thread slightly loose then fire some fluid through whilst another helper nips up the thread, that should force any air out.

HTH - Steve