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Brake Light Switch

PostPosted: Mon Jun 21, 2010 9:11 pm
by Galwaylotus
Ok. First off I have to confess I made a stupid blunder. I was changing the oil and filter on my S3 SE when the old filter, slippery with oil, slipped out of my hand. I discovered later that one of the connectors on the brake light pressure switch had broken off - probably knocked off by the falling filter! I had already considered replacing that switch with a pedal-mounted one. I cannot find anything in the shop manual about the switch. Was the Elan ever fitted with a pedal-mounted switch? If so, was it on the push-rod side or the peasl side? My car has a bracket with a 7/16" hole mounted just over the push-rod lever (see centre of photo - just behind the spring). Was that intended for mounting a switch?

Any help would be appreciated. Thanks.

Re: Brake Light Switch

PostPosted: Mon Jun 21, 2010 9:18 pm
by billwill
This was mentioned recently apparently the Sprints have a mechanical switch in the pedal area.

The S3 as you know has a hydraulic pressure switch.

But they are fairly standard car parts, so why not just get a new one. The exact type was mentioned on this forum not long ago & you should find it on a search.

If after fitting it you dab the pedal a few times without full travel any buble of air will probably rise up to the master cylinder, so you may not even need to bleed the brakes.

Re: Brake Light Switch

PostPosted: Mon Jun 21, 2010 9:26 pm
by alexblack13
Yes it was. A very simple pull to contact switch (via a spring). The pedal holds the contacts open. Popular mod fitting the hyd' unit to the sprint though, and if it were me I think I would consider keeping it. The pedal area type is a fiddly bit of kit and typically Lotus under engineered. Having said that its simple & light and works well enough if well fitted.

Think I would keep the original type though. Get a new hyd one.. Su Miller normally has the 'pedal' type. Be warned though they can be a pain in the ass to get right and you would need a small wiring mod.


Alex B.... 8)

Re: Brake Light Switch

PostPosted: Tue Jun 22, 2010 6:39 am
by oldelanman
Yes it was. A very simple pull to contact switch (via a spring). The pedal holds the contacts open


I don't know if the Sprint is different but my S4 has a plunger type pedal switch mounted on the pedal box - normally closed contacts held open by the lever.

You could consider this more "fail safe" than a hydraulic pressure switch - if you suffer a brake hose failure you will have no line pressure and hence no brake lights, the mechanical switch works as soon as you hit the pedal. So the 20 something mum following behind in her 4x4 on the mobile phone to her hair dresser and fixing her make-up in the rear view mirror, at least knows you intended to stop and might even brake herself. :)

Regards,

Re: Brake Light Switch

PostPosted: Tue Jun 22, 2010 7:28 am
by alexblack13
There is an internal spring.& pedal as I said holds the contact open..

20 something behind in the 4x4 is usually left in the dust while I go find somewhere to hide. :wink:

Take your pick. as I also said system works well. is simple.

AB... 8)

Re: Brake Light Switch

PostPosted: Tue Jun 22, 2010 1:00 pm
by oldelanman

Re: Brake Light Switch

PostPosted: Tue Jun 22, 2010 4:24 pm
by StoatWithToast
Yeah, still can't find either an hydraulic or mecahnical contact switch on my Sprint. I know there is one as I tested the lights before buying, now they are ... erratic and can't find anything to replace! Maybe I have an accelerometre that only turns them on under heavy braking ;)

I prefer hydraulic switches, but like I say, I can't see one on mine, or anywhere I could put one.

Re: Brake Light Switch

PostPosted: Tue Jun 22, 2010 5:44 pm
by alexblack13
Its liable to be in the pedal area bud! :wink:

Check out the picture above.. Looks like Roger's pedal box sitting on the bench ready for refurb' :wink:

Thanks Roger.. :wink: :wink:

Alex.... 8)

Re: Brake Light Switch

PostPosted: Tue Jun 22, 2010 7:41 pm
by billwill
The hydraulic one screws into a four-way brake-pipe junction mounted on the chassis sub-frame in the general area of the oil pump & filter. It's possible that if your Sprint came with a mechanical switch in the pedal box, that you only have a three-way junction there. Other alternatives are a 4-way junction with a plug screwed into one of the holes.

Re: Brake Light Switch

PostPosted: Tue Jun 22, 2010 7:52 pm
by Galwaylotus
billwill wrote:The hydraulic one screws into a four-way brake-pipe junction mounted on the chassis sub-frame in the general area of the oil pump & filter.

. . . and hence the resulting broken switch when my old oil filter slipped from my hand!! :oops:

Re: Brake Light Switch

PostPosted: Tue Jun 22, 2010 7:59 pm
by alexblack13
Butterfingers!!

Get a new switch!!

And don't do that again!!

:wink: :lol: :lol: :lol:

Alex.... 8)

Re: Brake Light Switch

PostPosted: Tue Jun 22, 2010 8:22 pm
by Galwaylotus
Nope. Oil soaked fingers! I am trying to get a new switch. I just don't want the hydraulic one. Pedal-mounted for me thanks. I tried to send an e-mail to Sue Miller but their website won't accept it. I sent one to Paul Matty for current price and availability so I'll see what response I get. Can't drive the car without it so I'm in a hurry! :cry:

Re: Brake Light Switch

PostPosted: Tue Jun 22, 2010 8:25 pm
by simonknee
I replaced the hydraulic one with a homebrew microswitch - the type with a lever arm and a roller bearing. My mounting bracket is rubbish but the fail mode is to turn the brake lights on. This is much better than the hydraulic one that fails with the brake light off.

More importantly it takes quite a push to activate the hydraulic switch by which time that 4x4 (SUV) is right up your trumpet. Plus with the pedal box switch a little press on the pedal activates the lights but not the brakes. Soon gets rid of the dick-wad on your bumper!

Call Sue, she always answers it seems (but she is snowed under at the mo')

Re: Brake Light Switch

PostPosted: Tue Jun 22, 2010 8:39 pm
by Galwaylotus
simonknee wrote:I replaced the hydraulic one with a homebrew microswitch - the type with a lever arm and a roller bearing.

Of course! I should have remembered that will work perfectly. Must get into Maplin.

Re: Brake Light Switch

PostPosted: Tue Jun 22, 2010 9:29 pm
by alexblack13
Nah! Get Susan to send you the right switch for the job. Give her a ring.The number is on the website & she always answers providing you are within the business hours. She really knows her stuff.

AB...