repeated brake light problems
 

Hey Folks,

I have a 911SC in which I have changed the brakelight switch a number of times (3 or so in the last few years). I always flush before.

Do I have something in my system that is causing the brakelight switch to fail over and over?

pedal feel is good
fluid about 8 months old
using dot5, (when i got the car it was in there)

is the master cyling eroding away?

Any ideas would be helpful.

ned
nedzaldivar@yahoo.com

Probably poorly made switches. The pressure sensor portion is theoretically isolated from the fluid.

Well i guess that is possible. I did buy the last couple from the local parts store. I will try porsche parts this time.

I also noticed a difference with some of them working in my car and some did not. The difference being a number on the unit. The ones that worked seemed to have a lower number.

Not sure what that is about, maybe sensitivity?

Most likely, i've never looked into that but the line pressure can vary a lot from one app to another.

I had the same problem on a '77. I must have put 10 switches in the thing. It all started when I changed over to silicone brake fluid. I changed back, but the problem continued. I bought them all at the dealer and no one could tell me why it was doing this.

Since it is assumed that the failure of these switches is from being clogged, why wouldn't it be possible to clean the old ones or soak them in some kind of solvent.

I just changed mine for the first time recently with new ones, but I was thinking of reusing the old ones if the new ones go bad.

Just a thought.

When I had my '88, I went through this routine as well. Some of the switches are VW interchange parts, and some are made in Mexico. Yet all are sold as Porsche parts by the average retailers.

I tried two sets of the switches, which turned out to be the Made in Mexico type, from a well-known new-parts retailer (not PP). They lasted about a year before needing excessive pressure to trigger. Finally I bought the "real" Porsche parts from PP.

The "real" made-in-Germany parts finally fixed it for good. I am still running the "Bosch" red relays that were made in China, though. :D

Just my experience. Good luck!

I heard similar stories...but the offending country of origin was Brazilian made switches with VW links. Look for German made parts usu from Porsche dealers....(even then it seems the Bosch parts are recently made in Spain or Czech Republic)... :(
---Wil

Even the newer Porsche switches are being made elsewhere and they aren't very good.

I replace my master cylinder and OEM switches came with it. So far, so good. If you are getting crud in your switches, you are due for a new MC. I was very impressed with how good the brakes felt with a fresh MC - you might consider this before spending the $50.00 plus on just two switches.

I would not go with the VW switches anymore. I will go for OEM parts and take a hard look at country of manufacture.

John

Crud in switches? How can you tell?

Should I be testing the MC, even though I have good pedal feel?