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shawn barker
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Brake lights aren't coming on under "normal" braking


My wife followed me home from Volksfarmers today and commented on the lack of brake lights on my 412.

They work if you stand on the brake pedal VERY hard but under normal braking do not come on.

I'm assuming that this is a switch problem? However there are two switches on the master cylinder and both of them require the same amount of HARD pressure to get any lights to come on. The car does slow down and stop under normal braking so that would suggest that the master is working.

So, does a Type 4 master cylinder use the same brake light switches as any other VW and if so which one?

Also, the way my luck is going is at the moment fitting a replacement would probably result in the master deciding to pack up, so is there another way of fitting a switch that works of the pedal? For example, using something like a courtesy light switch?

I want to get to VW action and Farmfest this year so am looking for a solution that will in no way risk damage to a master cylinder that would be very hard to replace and leave me unable to drive anywhere.
1/Sep/2009, 7:45 pm Send Email to shawn barker   Send PM to shawn barker
 
soundcatcher
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Re: Brake lights aren't coming on under "normal" braking


Hey Shawn, as I'm sure you know most modern cars use a normally closed push/micro switch that touches the arm of the brake pedal so that the moment the pedal is touched the switch is released and the lights come on.

If your switches need you to stamp on your brakes for them to work it sounds like they will either very soon fail or they have some muck inside them and only by stamping on the brakes do you move the muck enough to get some pressure in the switch.

Oh and why 2 switches??? Any idea what each of them does??? Maybee if you can work out if one is working and the other is faulty you can gerry rig your whole system through one switch??

Just been on the samba and it looks like your two switches work in tandem....kind of a back up system if one fails then the other hopefully will still be functioning. So maybee you shold test each one individually and try and work out if one is faulty or if they are both dodgy.

You might get away with a standard switch as a replacement. If it were me I'd give good old VW Heritage a call as they have the cross refences between the different types as to which parts are interchangeable.

---
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1/Sep/2009, 8:45 pm Send Email to soundcatcher   Send PM to soundcatcher
 
shawn barker
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Re: Brake lights aren't coming on under "normal" braking


Thanks for the reply

Both switches are unfortunately duff (I think that it is the technical term?)

I will need to make time tomorrow after work to investigate further the alternatives to removing the switches from the master cylinder as I obviously need brake lights to get around safely, especially on the motorways at the weekend.

1/Sep/2009, 10:51 pm Send Email to shawn barker   Send PM to shawn barker
 
soundcatcher
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Re: Brake lights aren't coming on under "normal" braking


Bummer (another technical term emoticon )

Good luck with getting replacement switches.

Never having set eyes on your master cylinder is it simmilar to a beetle or is it more a kin to a modern car??

I'm guessing your car is a dual circuit and there is 1 brake switch on each circuit allowing for either circuit to fail and still allow the brake lights to function?

If the switches are simmilar to beetles/ splitties then a pair of pliers or a spanner depending on the shape of the body of the switch should get them off easily. Can't remember where you will stand with bleeding the brakes. They will probably need bleeding as you would have breached the system?!

Good luck.

Andy

---
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Mark W
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Re: Brake lights aren't coming on under "normal" braking


If you are clever you won't need to belld the system.
I always place a plastic bag over the reservoir, then screw on the cap (this blocks the small air hole in the lid not allowing air in to the system) then whip the old switch/switches out quickly and screw in the new switch - you shouldn't have let any air in the system.
Obviously try the brakes to confirm they don't need bleeding before going out on the open road and doing some damage.

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2/Sep/2009, 8:40 am Send Email to Mark W   Send PM to Mark W
 
soundcatcher
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Any fool can make things bigger, more complex, and more violent. It takes a touch of genius - and a lot of courage - to move in the opposite direction.
2/Sep/2009, 9:47 am Send Email to soundcatcher   Send PM to soundcatcher
 
soundcatcher
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Any fool can make things bigger, more complex, and more violent. It takes a touch of genius - and a lot of courage - to move in the opposite direction.
2/Sep/2009, 9:48 am Send Email to soundcatcher   Send PM to soundcatcher
 
soundcatcher
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Re: Brake lights aren't coming on under "normal" braking


That's clever. Create a fixed pressure in the reservoir so that the system's overall pressure won't chnge when you remove the switches (one at a time so that there is only one hole in the system at a time) As long of course as you don't push the pedal. emoticon I'll remember this next time my switch goes...

---
Any fool can make things bigger, more complex, and more violent. It takes a touch of genius - and a lot of courage - to move in the opposite direction.
2/Sep/2009, 9:51 am Send Email to soundcatcher   Send PM to soundcatcher
 
Mark W
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Re: Brake lights aren't coming on under "normal" braking


See - I am not as silly as I look!! emoticon

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2/Sep/2009, 4:41 pm Send Email to Mark W   Send PM to Mark W
 
shawn barker
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Re: Brake lights aren't coming on under "normal" braking


Just need to confirm now that a Type 4 switch is the same as other ones that are available.

However I think I might have a backup in the rumors that there might still be a few NOS ones floating around in the club stores somewhere...sshhhhhh!
2/Sep/2009, 5:49 pm Send Email to shawn barker   Send PM to shawn barker
 


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