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1978 911SC Brake Warning Light


Vehicle Information: Model: 911sc; Year: 1978; Body Type: Coupe; Total Mileage: 118159;

I read the response to the 1982 dash warning light activation and I havea similar problem, although my light only activates when I place the carin reverse and back-up with light pedal pressure. I have reset the lightand cannot get it to ever activate while going forward. Back-up once,light pedal pressure and, bang, on comes the light. I have rebuilt allcalipers (set all pistons with ATE angle gauge) rebuilt master, new pads,new master switches, braided brake lines and pressure bleed system with"Motive" bleeder. The brake pedal is hard and the brakes work excellent.The light will not activate while moving forward; only in reverse. Itried unplugging each switch to see if a specific circuit is/was failingbut the light comes on with either one connected (again only in reverse).I researched many help sites and was advised that it was the mastercylinder. I have just installed a new master (direct from my Porschedealer) and the same problem occurs. The rotors are within spec forthickness. Some one suggested it was the power booster can, but per thetech book, it seems to be functioning. I can lock up the brakes with onlyslight pull to the left under skid. At 60+ I can bring the car to acomplete stop in about 30 feet with no lock-up, so I'm sure the brakesare functioning. This light is driving me crazy!

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