Lotus Elan

Sprint Original brake light switch correct assembly please

PostPost by: bloodknock » Sun Jul 15, 2018 3:15 pm

Hello People
Years ago when dismantling the car my brake light switch went ping, distributing parts to the three corners of the Bermuda triangle. I searched and recovered what I could find. See photos:
20180715_153241.jpg and
20180715_153207.jpg and
20180715_160550.jpg and
20180715_1529101.jpg and
20180715_153218.jpg and

Can any knowledgeable person out there tell me:
(a) is there any part missing?????
(b) Which way should it be assembled? [Im thinking it should be normally open - closed when the pedal is depressed, but the copper washer moving contact could be assembled so that the switch is normally closed.]
A worry is that there is very little travel when operating as a normally open switch, and there is a fair bit more travel in the brake pedal!
If it is assembled with the copper conducting washer in position A (see diagram) there is significantly more over travel.
Regards
Bob
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PostPost by: jimj » Sun Jul 15, 2018 4:50 pm

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PostPost by: oldelanman » Sun Jul 15, 2018 8:47 pm

Hi Bob,
The switch should be assembled to be normally closed (washer in position A in your sketch). Once installed, the contacts are held open when the brake pedal is at rest and close when the lever moves away as the pedal is depressed. When you install it don't screw it in too far or it will act as a pedal stop and fail again pretty soon.

pedal-box-assembly-003.jpg and


As you can see my switch also came apart and I repaired it by melting the two halves together with a soldering iron - not pretty but it's lasted for 30 odd years. :roll:
Roger
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PostPost by: rcraven » Sun Jul 15, 2018 9:05 pm

I was trying to remember exactly how the switch fitted but don't need to now after Roger's post. I did something similar to mine when it came apart in 2003 when I was replacing the pedal rubbers the day I was about to go on holiday. I glued it back and never needed to replace it.
Robert
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PostPost by: nigelrbfurness » Mon Jul 16, 2018 8:32 am

This is a very common problem with these switches and really you should replace it with a new one, they are readily available and cheap as they were standard on Minis and other cars of the era.
1970 S4SE/1760cc big valve/SA-AX block, L2s, 45DCOEs, 1978 Jensen GT, 1962 AH Sprite, Alfa-Romeo 159, 1966 Bristol Bus, 1947 AEC Regal bus.
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PostPost by: bloodknock » Mon Jul 16, 2018 9:19 am

Thanks Chaps
Last night after I had posted this enquiry, I suddenly realised that I had been thinking about the switch the wrong way around ..... When the pedal is depressed the plunger is allowed to relax outwards so that is when the contacts should make. I was originally thinking that the switch was pushed in when the pedal was depressed! I did take it off the car some 35+ years ago!!!
Thanks for straightening me out!
Regards
Bob
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