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Posted by: flipb Apr 15 2010, 07:29 PM

My '74 has a 19mm Master Cylinder.

The dash warning light has been flashing incessantly - I disconnected it a while ago. Tonight I was busy breaking my horn mechanism in the steering wheel and I decided to try to reset the button on the MC to stop the flashing.

Here's the deal. With the car on the ground and a flashlight, I managed to find the reset button. Hit it, reconnected the warning light on the dash, and it now functions correctly. (stops when the parking brake is released)

However while I was reaching in there, I accidentally disconnected what looks like a Ground wire. I don't think I have any hope of finding where it connects without taking the car to a shop and getting it up on a lift, so...

What is the risk of driving it with the ground wire disconnected from the MC?

I don't think I've ever fixed something on this car without something else. If it's not one thing, it's another. (Or as Freud put it: If it's not one thing, it's your mother.)

Posted by: dr914@autoatlanta.com Apr 15 2010, 07:43 PM

early cars two prong switch late cars single prong switch. the factory figured out that the switch can ground through the master cylinder!

QUOTE(flipb @ Apr 15 2010, 06:29 PM)

My '74 has a 19mm Master Cylinder.

The dash warning light has been flashing incessantly - I disconnected it a while ago. Tonight I was busy breaking my horn mechanism in the steering wheel and I decided to try to reset the button on the MC to stop the flashing.

Here's the deal. With the car on the ground and a flashlight, I managed to find the reset button. Hit it, reconnected the warning light on the dash, and it now functions correctly. (stops when the parking brake is released)

However while I was reaching in there, I accidentally disconnected what looks like a Ground wire. I don't think I have any hope of finding where it connects without taking the car to a shop and getting it up on a lift, so...

What is the risk of driving it with the ground wire disconnected from the MC?

I don't think I've ever fixed something on this car without something else. If it's not one thing, it's another. (Or as Freud put it: If it's not one thing, it's your mother.)

Posted by: McMark Apr 15 2010, 07:47 PM

The wiring harness has two connections. Let the other one dangle. It was already there, you just didn't notice it before.

Posted by: jt914-6 Apr 15 2010, 07:47 PM

Is the wire connected to the master cyl. switch brown with a yellow stripe? It should be connected to it if your switch has a reset button. On the orignal switch there were two wires. The "ground" you think you disconneted is solid brown and IS a ground, except with the one wire switch it is not used...connects to nothing....

Posted by: flipb Apr 15 2010, 08:04 PM

You all overestimate me.

I actually did screw up, I think. See below.

It looks like the solid brown ground wire was clipped by a PO, presumably when the 19mm MC was installed. The brown/yellow stripe is the one I accidentally knocked loose.

Anybody have a good photo to show where it connects? Alternately, is the risk of driving just that I won't get a warning light if I lose hydraulic pressure?

Posted by: McMark Apr 15 2010, 10:11 PM

Hooks onto that big white thing.


Attached image(s)

Posted by: Eric_Shea Apr 15 2010, 10:38 PM

No, no, no...

It hooks on right here:


There should be a male spade on the back of the tie-rod end there.

Geez Mark... full of bad advice today aren't we?

Posted by: McMark Apr 15 2010, 10:49 PM

What the heck you talkin' bout..........

Posted by: Eric_Shea Apr 15 2010, 10:50 PM

(sorry... couldn't help myself)

Posted by: Dave_Darling Apr 15 2010, 11:41 PM

The electrical connection is on the same thing that the reset button was on. Looks like that white thing in the pic is it, but I could be mistaken.

If you want to be sure, remove the gravel pan so you can get a good look at everything. Maybe put the front end up on jackstands (so we know it's a real 914!) so you can really get a look.

--DD

Posted by: McMark Apr 16 2010, 10:48 AM

QUOTE(Eric_Shea @ Apr 15 2010, 09:50 PM)

(sorry... couldn't help myself)