I replaced the two brake switches which attach to the master cylinder and now the brake lights work perfectly.

I could not, however, tighten the new switches enough to have the switch become flush against the master cylinder. The switch became extremely hard to rotate, so much so that I thought i might strip either the threads of the switch or the master cylinder.

I have no doubt that the switch will not come loose. I was using a 22mm socket and rachet and generated a lot of force in order to rotate the socket.

Nor do the switches leak fluid.

There remains about an 1/8" gap between the switch and the master cylinder.

Also, I was really surprised how much force it took to loosen the old switches. And it still took quite a bit of force to rotate the switches once they were loosened. Ultimately, the switches could be loosened by hand. But it took a number of rotations to do that.

Is this normal.

Last, I note that the switch did not come with a gasket. Therefore, I presume that the threads function to prevent leaks, not the face of the switch against the master cylinder.

Any insight would be greatly appreciated.

John.

 

Not sure how hard is yours but on mine, it has some friction, not as smooth. They are in there for months now no problem.
I bought mine from Autozone. The prongs are wider than my stock therefore I have to make an adapter for each of them.

 

I am confused. Were you able to make a flush connection?

 

Also, I got factory porsche switches. ( I got a good price after threatening to cancel my order because I could get the switches cheaper from Volkswagen. ) The prongs fit perfectly.

 

The brake switches on these cars use pipe thread, meaning that it is very gradually tapered, so that it seals. Don't worry, it is not supposed to seat all the way against the master cylinder. When it gets very tight and hard to turn, that usually mean that it is tight enough. You are right, loosening old NPT brake switches on these cars can be a bitch, especially since u don;t have tons of clearance for a wrench so u can get good leverage. 356s use pipe thread for the oil drain plug next to the sump plate, those things can be a pain in the *** if they haven;t been off in a while!

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Chris Andropoulos
Schneider Autohaus
Santa Barbara, CA

 

thanks Chris.