Hi Folks" I just upgraded to '85 911 brakes. In the process I also went to a new 19mm master- come to find out my car already had the 19- replaced it anyway. Quiestion is- the electrical connection to the MC-one lead and my car had two leads disconnected in the boot. I tride them- got a flashing dash brake light- What to do? I'm sure I can just run without the light as I had, but just wanted to know. 73-2.0 Greg

Two different styles. Just pull the switch off the old master and put it on the new one. If the light still flashes, bleed the brakes until it doesn't.

First one was never connected-I do see a brown ground wire.

Is there a reset switch on those?

just had this problem. replaced the switch in the new mc with the old one. works great now. there is also another thread about this. that shows the reset button in a picture.
but i don't think the 19mm has the reset switch , can't remember for sure.

pic thread

You don't need to swap the switches, though. One switch has two connections on it; the brown/white wire goes on one and the plain brown goes on the other. The other switch has only one connection; the brown/white one goes on it. Tape the brown wire up out of the way somewhere.

If you put a two-connector switch in place of the one-connector one, find the brown wire somewhere in the area and hook it up--or just run a wire to a ground and hook that ground wire to one of the connectors.

The original switch grounds through a separate wire--the brown one. The newer-style switch grounds through its threads. Same function, slightly different ground path.

I figure it's easier if you don't open up the MC and potentially allow any dirt to get in there.

--DD

QUOTE (Dave_Darling @ Nov 30 2005, 04:23 PM)

I figure it's easier if you don't open up the MC and potentially allow any dirt to get in there.

just tape up the brown wire and connect the other.

if your brakes are bled (and working) and the light is still blinking, see if your new MC has a reset switch.
if so, press it in, you'll have to do that after every brake-bleeding ...

Andy