84 TA, stock 4 wheel discs. The proportioning valve is leaking at the little plastic switch that triggers the brake warning lamp inside the car. Does any know what the switch is called and where I can buy a new one from. None of the parts stores I called had any idea about it. Dealer was no help either.

I unscrewed the switch and didn't find any gasket to seal it against the proportioning valve body. Is this normal? Should I just crank down real hard on the switch? It's plastic so I'm afraid of breaking it.

 

IIRC there is, or is supposed to be, a o-ring on it.

 

I didnt see any o ring on mine but i cranked down on the switch it and it's not leaking any more. I can't get the brake warning lamp to go out in the dash though. Doesn't it go out when you push real hard on the brake pedal as long as they are no leaks? I just redid the entire rear brake system, lines, calipers, pads, rotors and hoses. I bled the rear brakes too. Pedal feels nice and firm. I wasn't able to get the front bleeders to open so I may have to replace those calipers too. But for the time being I thought the brake light should go out as long as nothing is leaking.

 

From the manual:

The pressure differential warning switch is designed to constantly compare front and rear brake pressure from the master cylinder and energize the warning light on the dash in the event of a front or rear system failure. The valve and switch are so designed that the switch will latch in the "warning" position once a failure has occurred. The only way the light can be turned off is to repair the failure and apply a pedal force to develop approximately 450 psi line pressure.

Either the switch is defective or you have a failure in the system.

JamesC