Early Car Brake Master Cylinder switch problem

[rexav8r]

[I also posted this over on Pelican]

Early car, 1970 911E

The red light on the top center of my Tach stays illuminated red.

There are two things that cause this. 1) the hand brake switch is making contact (i.e. the lever is raised) or 2) there switch on the master cylinder indicating there is a problem with brake pressure in the master cylinder.

I played with the adjustment of the switch on the hand brake via the adjustment screw and assembly. That didn't work, the light stayed on.

I got under the car and disconnected the wire/s from the switch on the master cylinder and the light went out. Reconnected them and the light came back on. Therefore I think it's that switch.

The brakes had gotten fairly spongy but I bled them and they brakes are performing perfectly.

Here are my questions:

1) Is this switch serviceable? Can I clean it somehow if I take it out?

2) Is it possible that there is one brake line I didn't bleed properly that could be causing this? -or something with the Brake Fluid Reservoir? I am going to try to re-bleed them this weekend or next week to see???

3) I tried to replace most of the fluid during bleeding, but I may not have. Could this have an effect on the switch??

4) The switch on the M.C. has TWO wires connected to it. This is an early car switch, the ones I have seen recently (on replacement Master Cylinders) have only ONE wire hookup. Which wire do you hook up and what do you do with the other wire? -does it assume that the threads of the switch are grounded??

Any other ideas???

Thanks!!

[edmayo]

I just leave off the offending wire. If a brake circuit fails you'll be the first to know without any warning light. Seems like there is a reset button in between the spades if my memory is right, try that first.

[911pcars]

I leave my light ON. It's a good conversation piece. "It warns of incipient brake failure".

Sherwood