TheSamba.com :: View topic

Sun Jun 24, 2012 2:23 pm

I have searched, but don't seem to find any topics on an alternative to the pressure type brake light switch on the master cylinder.

I just finished replacing the brake light switch(s) on my MC this afternoon. It is the third time I have replaced the switches in the four years I have owned the car. And yes, they are the German switches from WW.

It wouldn't be quite so bad, but there is almost NO space down there to get a wrench in and remove and replace the switches.

Has anyone tried anything different to control the brake lights? Years ago, I seem to remember someone adapting a normal type switch to their 914, but I can't seem to find that post either.

Thanks

Sun Jun 24, 2012 2:29 pm

I had seen a post where someone had fabbed a bracket and used a momentary contact switch to activate the lights.

Sun Jun 24, 2012 2:55 pm

what year?
are you burning them up with shorts in the brake lamp lines.
if yes, you will burn up any switch. (or if huge switch then the wires burn)

is yours still wired to the factory fuse.? if yes, is the fuse the right size
or does it blow out? the switch, does it look overheated?

I buy from bughaus.com , not one failed buy yet,
i have 50 bad parts from all the others.. this year.

it has 2 functions ( i guess yours is the double units failing?)
one is to warn of brake failure
the other is brake lamps (pair)

take off left front wheel to get access.
the switch should not fail. period
if it does
it's junk
or there is a short. ( they catch fire all the time here. for 2 reasons)
(30amp fuse added, and shorted lamps.) takes 2 errors.(one by man ,one by bad luck)
did you know that the bulbs scan sort INSIDE the bases? of individual lamps.
(the bond breaks inside)

yes, you can add a switch to any brake on any car.
a bracket and a switch.

on mine there are 3 switches,
1 is warning. it warns if there is pressure differentials on the FRONT to REAR.
the other 2 form what is called a WIRED "OR" logic gate.
this wired-or,
turns on the brake lamps
IF Front OR rear make pressure.
they are diaphram switches. and F1 fused.

in 74 (random pick) they have 3 pin pressure switches for the lamps
with a dual circuit brake warning module.
quite different. and uses ign fuse F11

Sun Jun 24, 2012 3:57 pm

The 914 switches are the same part as Beetle switches, going by the part numbers, so that won't be a help.

Sun Jun 24, 2012 5:21 pm

Have your switches failed electrically, or did the brake fluid start to leak?

If it is electrical, you could try adding a relay after the switches. This reduces the current flowing through them, prolonging their life.

Sun Jun 24, 2012 6:48 pm

I should have given more details. The switch works fine and then it suddenly takes more and more pressure on the pedal to get them to light until finally no more pressure will work. There are no leaaks. I replace the switch and they work fine again for awhile. Usually a year. The switch does not fail electrically.

Sun Jun 24, 2012 8:10 pm

Curiosity got to me, so Iust went to the garage to check on the brake lights on my 71 Convertible. Brake lights worked fine, and I didn't have to stomp the pedal all the way down.

I keep detailed records. Back in 2004 I had issue of having to stomp on the pedal really hard to get the brake lights to come on, huge safety hazard. So June 2, 2004 I bought two new 3-prong brake switches at BAP, a local parts chain here in Arizona, part number 113-945-515G and installed them. I don't know where those brake switches were manufactured, but BAP seems to stock parts that customers won't be returning/going Internet.

My brake master cylinder (71 Super Beetle) is an AutoZone #11-1551 rebuilt, lifetime guarantee, installed January 16, 1994.

Mon Jun 25, 2012 7:27 am

If the brakes are working fine, then I suspect bad switches. It happens. I got some from local foreign car parts store and had 3 fail within a week. Try a different brand. The ones I had probs with were Olympic or something like that.

Mon Jun 25, 2012 8:03 am

my brake lights work right when i touch the brakes. My third brake light is a different story though. I dont know how its hooked up but it either is on all the time or off all the time. And if its off all the time, i can MASH the peddel to the floor to get it to work but then it doesnt turn off. I might splice into my existing brake lights to make it work.

Sat Sep 15, 2012 4:17 pm

I own a 1971 Super Beetle 18 years with 4-wheel disc brakes. Over the last few years, I’ve found the quality of replacement brake light switches to be going down, both in component longevity and that new replacement switches seem to take more pressure applied to the pedal to make the brake lights come on. I’ve replaced the brake light switches in my Super many times in the last few years, it never gets better. This is commonly referred to as “lazy” brake lights, which is common on cars with disc brakes due to the lower line pressure required to stop the vehicle.

I live in a major Metro area and have had some close calls with people nearly rear-ending me. Hence I want to fix this issue.

I am leery if another new brake light switch will completely fix my issue, since I run disc brakes. Any thoughts?

Another solution would be to retrofit my car with a brake pedal-activated brake light switch, similar to most cars built from the 1960-onward (plunger-style switch). Has anyone tried this? I have some ideas and would like to see what others have developed. Any information is appreciated!

Sat Sep 15, 2012 5:54 pm

CarlIseminger wrote: And yes, they are the German switches from WW.
Try genuine VW switches from VW.

Sat Sep 15, 2012 8:20 pm

Three switches in four years sounds about right.

Here, Marc at STF, suggests using a mechanical switch tied to the pedal.

http://www.shoptalkforums.com/viewtopic.php?f=18&a...41592cf2d0

Sat Sep 15, 2012 9:36 pm

Sun Sep 16, 2012 7:53 am

I too was unhappy with the action of the brake light switch. I installed a spring loaded switch behind the brake pedal. This switch is a common item used in antique cars. I drilled a small hole in the brake support and connected it to the switch with highly flexible strong wire.
I adjusted the wire length so that when the brake is depressed one quarter inch, the brake lights activate.
No more time delay from first hitting the brakes to activation.
The switch can be found here:
http://www.speedwaymotors.com/Universal-Mechanical-Brake-Light-Switch,1972.html

Sun Sep 16, 2012 12:21 pm

Wow. This is exactly what I was looking for. Something that didn't depend on the brake fluid pressure to activate the switches. This seems to be so common for us beetle owners, one would have thought something like this would already be available for us.

And this was the same type of setup at the 914 that I was referring to earlier.

Thank you for the ideas.

Tue Sep 18, 2012 4:27 am

The setup of the last switch is very cool.

I would just point out two things about moving to a single brake light switch...
1) With a single switch, you loose the redundancy of two brake light switches. In the stock setup, if one switch failed you still had a second switch to operate the brake lights.

2) If you do not have functioning brake switches installed in the MC, the brake warning lights are disabled. Some people will tell you this is not important since a failure of the front or rear portion of the MC will be noticeable as a "low pedal". This may be true to the person who wrenches on the car, but I'm sure my mom would not know even if it happened to her while driving. But she would tell me that a red light in the dash has turned ON.

Tue Sep 18, 2012 5:53 am

My master cylinder doesn't have the third switch for the brake warning lamp. And I discovered, that while having the two switches for "incase", when I replace both switches, they must both go bad at about the same time. When I finally realize that my lights aren't working, I always check both switches and find that obviously, one has failed before the other as now neither of them are working, again.

Tue Sep 18, 2012 7:46 am

Guys that put aftermarket rearset assemblies on motorcycles often put in an inline brake light switch in. It is pressure based, but they do exist if you want to go that route.

Tue Sep 18, 2012 8:21 am

CarlIseminger wrote: My master cylinder doesn't have the third switch for the brake warning lamp.
Do your switches have 2 or 3-terminals? The 3-terminal switches have a built in Brake Warning switch when used in pairs.
Even if you have the 2-terminals switches, installing a pair of 3-terminal switches will give you the Brake Warning switch function. Most pre-'69 MC that used three switches have probably been upgraded/replaced with the more modern two switch MC.

CarlIseminger wrote: And I discovered, that while having the two switches for "incase", when I replace both switches, they must both go bad at about the same time. When I finally realize that my lights aren't working, I always check both switches and find that obviously, one has failed before the other as now neither of them are working, again.
Quite possible, but rarely do they fail at the same time/same day. This means when one fails you still have a working brake light.
If it is a mechanical failure, the Brake Warning light could tell you one has failed. If it is an electrical failure (eg. carbon build up) you may not know there is a failure until BOTH switches fail and your brake lights stop working all together.

Tue Sep 18, 2012 10:20 am

So how would I know when one of the switches fails? Yes it is great that there is a back up, but unless there was a way to be notified that the first switch failed, it isn't until I notice I don't have brake lights that I check the switches. So obviously both switches have failed. At the same time? I doubt it too. So one failed at one point and then finally the other one gave out. And they don't fail electrically. They fail to go on with the pressure.