Brake Light Switch

[Dave B]

Car is a 2000yr K series. Brake light switch seems a little dodgy. At MOT brake lights no worky, take off pedal cover and jiggle piston on switch and it works. Is it possible to fix the switch or is a replacement necessary. If replacement, is it a CC part or fron donor vehicle. Parts are a little hard to source in Gran Canaria. Any thoughts??

 

Dave B

[tweeky]

Take the switch apart and you can clean the contacts do a serch on here and im sure you`ll find out how

 

 

 

Tweeky

 

to infirmity.................... and beyond

[Nick Chan]

Yep, easy fix. Remove the switch from the car and with a small screwdriver or point of a knife, you can easily remove the back of the switch. Make sure you catch the spring that will try to escape! There are a couple of small contacts that get a little of crud to be cleaned off. Whole job probably takes less than 5 mins

 

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Back in a BEC! - but done alright in Class 1...

[paul abrahams]

Available from Caterham at Dartford and the online store, sorry i can't do linky things. Cost somewhere in the region of a fiver, always carry a spare, they pack up regularly but are relatively simple to clean, but get a spare

[TomGaval]

Funny, I have a 2000 Superlight, that got black flagged at a track day this year for my brake lights being stuck on. Took the pedal cover off and found that the locking nut had worked it's way loose. Just ordered a spare to be safe, but the original one, once tightened seems to be working ok now.

 

Tom

[Bricol]

Adjust the operating flag so it doesn't bash it to hell and back - mine has worked fine for the last 10yrs after a quick rebuild and adjustment in the first month.

 

Bri

[Dave B]

Thanks for replies. It was as easy as everyone said. Now all worky!!

 

Dave B

[patneale]

I had this problem on both my Caterhams. My first one a 1.6 1999 K series, failed at 12,000 miles and I got a replacement at local Motorspares shop. Think it was a Renault one. Second car 2003 1.8 Xpower SV same thing at similar mileage. Took apart and cleaned it, but as there was the addition of Hi Visiability LED Redlights mounted on the top of Roll Bar rewired the switch via a headlight relay so old switch takes almost no current and is still working at 42,000 miles. There is a slight click as the relay operates and this is a useful check that all is well.

[Martin J]

rewired the switch via a headlight relay so old switch takes almost no current and is still working at 42,000 miles. There is a slight click as the relay operates and this is a useful check that all is well.

What a good idea I think this might be my next upgrade.

The fundimental problem is the contacts having to cope with 2x 21w bulbs & in addition on mine the high level brake light.

[Bricol]

You might be surprised if you looked inside the typical 40A relay used on motor cars and compared the size of the switched contacts with the contacts inside the brake switch . . .

 

Problem with the Caterham switch is as mentioned - incorrect setup. You are more likely to suffer a failure with the back emf from the relay coil ruining the switch contacts than brake light current (2 x 21W = not a lot. LED = even less). It obviously works, but to my mind, adds another potential problem. Keep it simple.

 

Take a decko around the brake pedal on the your average tin-top (and clutch pedla on a lot - same switch there to tell the ABS ECU complicated things) - same switch setup idea, just with less ability to be set-up wrong. Even my the ones behind the pedals in the integrale have done close to 200,000 so far.

 

Bri

[Stationary M25 Traveller]

Agree ....... relay contacts are tiny ! Standard brake light switch is fine as long as you make sure the legs inside the switch are squeezed together and any sticky crud cleaned off the internal contacts as part of your service schedule on the car.

 

 

[patneale]

As far as I am conserned you can stuff all your theories on back EMF from relays. The facts are:- I have had about 30 cars over 45 years and driven well over 1,250,000 miles and never had a headlight relay failure and until I had Caterhams had never had a brake light switch failure. 2 failures in 2 new Caterhams both under 15,000 miles would in todays world indicate a poor quality switch and I have never ever seen any suggestion that a brake switch should be "serviced" as part of normal running repairs on any car. My mod has lasted nearly 17,000 without fault. The load is under half a normal headlight relay load. They should work for the life of the car untouched as all have done on other cars. Caterham have always been lucky as their warranty on average only covers the cars for about 3000 miles which is the average one years use of a Caterham. So many failures which on normal cars which would show up with their greater mileage do not come up in Caterhams radar as a problem item as it is not a warranty claim.

Another Caterham weakness on the K series engine is the oil pressure sender. After 5 replacements, most at Caterham's expense as they lasted less than one year, I modified the whole set up and removed the sender from the oil filter housing and fitted it to the clamp bolts for the headlight stay just under the back of the nose cone via a long braided oil pipe and connecting lead. It is away from any wet and vibration and has lasted nearly 15,000 miles and gives lovely high readings.... never less than 4 1/2 Bar hot. Cost under £20. Caterham reckoned that wet and road dirt was the problem, but it wasn't as I covered it over from wet and dirt and it still failed. It seems that it is engine vibration which ruins the senders ( These are not a "Rover " original unit as the instruments are different) It is possible that the crimped metal around the plastic sender unit loses its grip due to engine vibration and oil slowly makes its way into the electrical parts causing failure. ( It was the only failure of a part on the famous Caterham which did the 2004 Nurbergring 24 hours race and came 11th overall !) Most Caterham Owners have replaced the whole sender and instrument for a non electrical set up, but that is quite expensive compared with my modification.

A car manufacturer is only going to put a better quality part into their cars if it costs them under the warranty. Selling parts after warranty is good profitable business!!

Just about to fit a new foam oil baffle in the sump of my 42,000 mile K series when weather warms up! Sump gasket at £40 is expensive !... Total of 56,000 miles in Caterhams now and apart from petrol, never needed any oil, brake fluid or water ever between services... An excellent record !

[Stationary M25 Traveller]

Sump gasket at £40 is expensive !

Are you replacing it then ? Never needed to do that. Now you have opened the box of frogs (or is it Devil's Spawn ?) marked sump foam 😳 😳 😬

 

 

[jakeandlizzy]

Yep, cheap switch like various other skimped areas on the car for sure (throttle cable and pedals, switches........etc...) . Just buy a good switch from some other car (search the forums) and modify a bracket or use a high quality microswitch, again with a different bracket ... the solution to take it apart every few thousand miles and clean it is a no go!

[Bricol]

It doesn't need cleaning - it's simply set wrong at build. Normal operation will wipe the contacts clean. It's the same type and make of switch as supplied as spares in your local factors for your tin-top. But your tin-top doesn't have it set incorrectly as often, so doesn't drive the bridging contact too far into the fixed ones, so they don't fail in the same way.

 

Once you figure that out, which will involve dismantling the switch, you're fine. 10yrs, over 40,000 miles of use (it did sit still for a couple of years while I worked away - and then became my everyday car as it was the only one legal when I came back), it still works. So I'd say incorrect assembly rather than crap component. Simply position the switch, or bend the operating flag, so that it just switches off when the brake pedal returns, rather than driving the plunger so far into the switch, it permanently adjusts the contacts to wide open.

 

As for load - it's wayyyy less a load than two 55W headlamps - but it's not the load that causes switches operating relays to fail - it's the EMF from the relay coil at low current that bug gers the contact faces as you switch it off - and once correctly set-up, I'd still say there is more likelihood of that causing failure than the approx. 3A standard brake lights will pull.

 

This'll no doubt jinx it, but my carefull routed throttle cable is still fine, correcly set-up clutch cable is still working, pedals still move and operate what they are supposed to . . . A little bit of care and common sense to maybe adjust the basic Airfix kit of a Caterham, and there's not much to go wrong . . . I do keep inspecting the de-dion tube though . . .

 

Oil pressure sender is indeed a dodgy part IMO - so I removed the second one (that I lathered in sealant to make it last a little longer) it and fitted a mechanical guage from Burton Power - that still works after 8yrs.

 

I'm all for improving things, but coming from an engineering viewpoint, adding cost, complexity and weight doesn't count as an improvement for me. And I really hate spending money, as an honourary Tyke.

 

however, I did remove the ECU and replace it with an Emerald - that allowed me to find the missing 50 odd horses I knew were in there

 

Bri

[jeremybu]

Just get rid of it and fit a motorbike switch instead.

[marshall cook]

Or you could fit one of these. Brake lights would come on during any deceleration. Very confusing to other track mates wondering about your braking points!

 

here

 

MartyGator