Stop lights!

[ClickClickBoom]

Well my brake/stop taillights took more and more pedal pressure to activate the taillights. I got a master cylinder switch and started in. First thing I took apart was a switch that was near the gas pedal but was actuated by depressing the brake pedal. After removing this switch and checking it with an ohm meter I determined that it was not making proper contact. I drilled out a brass tube rivet end and opened the switch up and burnished the contacts, this allowed the switch to work properly. I then jacked up the car and removed the steering rack shield which allowed access to the master cylinder. I removed the switch on the side of the master cylinder and replaced it with the new one. I expected fluid to come out of the master cylinder, but was suprised when none came out. Now movement of the brake pedal more than 3/4 of an inch, actuates the lights.
All in all a 2 banana job and took 1 hour.
eric

[kidrock]

That's very cool. You've inspired me to gitter done on mine, now. Good job!!!

[ninelevenick]

I'm confused. Was it a combination of two malfunctioning switches that caused the tail lights to not work properly, or was it mainly the switch by the accelerator pedal that was the main culprit?

[Craig_D]

Do you have any pictures? I'm interested in this fix, as my brake lights also take too much pedal effort before they activate...and I really want to remain "punt free" while driving in traffic.

[ClickClickBoom]

Craig,
I was in the heat of battle, and neglected to take flicks. This project is easily a 2 banana job, very straight forward, the hardest part was jacking up the car. Very simple, basics. If you take the switch apart via drilling/grinding the tube rivet you will need a very small bolt and nut.to bolt the rivet back into place, or use epoxy, either will work fine.
Once you dive in you will see how simple the fix is.
eric

[Walt Fricke]

Careful, guys.

The '75 uses the brake pedal switch to turn the brake lights on. Whatever attaches to the master cylinder is to actuate the "brakes not working" light system.

The later cars, with vacuum power boost, use a different system. No pedal switch, the switches screwed into the MC (2 of them) control the brake lights and the warning light.

[Craig_D]

Hey Walt, I'm in Boulder as well...not too nice for our P cars this weekend huh?

Yeah, that's why I wanted to see pictures of this modification. I am planning to refresh my pedal cluster with bronze bushings one of these weekends and was thinking of just adjusting the brake light actuator at that point and see if I can get light with a little less pressure. I'm new to the 911 so I'm assuming there's an "easy" way to adjust the actuator...we'll see I guess.

Any suggestions with pics, are welcome!

Cheers,

- CraigD

[ClickClickBoom]

Walt,
My car is a '75 as you noticed. The switch on the master cylinder was not making contact/no contact when bench actuated, the new switch for the master did have a on/off actuation as a new switch. I have the FSM and the flow diagrams give me a headache. Will look tomorrow, thanks for additional details.
eric

[Walt Fricke]

Craig D

Your '78 pedal cluster does not involve any switches, so that is not part of installing new bushings.

Your MC up in the trunk area behind the dash (where it is lots easier to work on) has two pressure switches, each with three contacts. These combine the function of brake light switch with brake failure indicator. These switches have a rather shorter half-life than one would wish - their internal seal fails, a little fluid gets inside, and they don't work right after a while. If you think your brake lights don't come on as they should, just replace these switches.

I bet if you search the archives here for "pedal cluster" and "brake light switch," you will find plenty of posts, some with pictures.

I live in south Boulder overlooking the Tantra sledding hill. Snowy weekends are always a joy, with kids, dogs, and parents all over the hill, right out my window. With my 911 tucked in my garage.

Walt

[Chuck.H]

On my '89 carrera, I got tired of replacing the M/C pressure switches, plus I didn't like the way the brake lights didn'tt come on when in very slow stop and go traffic (look in the chrome of that F-450 behind you and you can tell how hard you have to press the pedal to get your brake lights to come on).

So I stopped using the pressure switches and wired up a standard brake light switch to press against the actuator rod on the front of the M/C housing. Now my brake lights come on with the lightest touch of the brake pedal.

Sorry I dont have any pics, but if you pull the plastic plug off the front of the M/C support housing you will see the actuator rod. I fabricated a bracket and bolted it to the housing...

HTH,
Chuck.H
'89 TurboLookTarga, 310k miles