Last month at the IPD Garage Sale I bought a complete set of vented rotors, calipers, and pads for the front brakes on my 1978 242. After swapping this new equipment onto the car, which badly needed it, I noticed that the brake failure light was coming on. After several bleeding sequences using the Motive Power Bleeder there was no change. The car was driven for quite a while with a spongy, yet functional brake pedal. Since the brakes were still working fine, I was convinced that their was still air in the system, and that it would work itself out over time through successive brake bleedings. Despite several further bleedings, the problem remained.
Two days ago, when I went to bleed the brakes on more time, I noticed that the rear passenger’s caliper had started to leak out of one of the piston seals. “Ah ha,” I thought, “this must have been the cause all along.” I ordered a new caliper from a local CarQuest ($44), installed it, and… still got the same spongy brake pedal and brake failure light. IPD sells their rebuilt calipers – same Ate brand – for $105.50 (less $27.50 core) = $78.00 and YOU have to pay shipping to return the core.
After consultation with some of the gurus on turbobricks, it seemed likely that the brake master cylinder had failed. I ordered a remanufactured one from local parts supplier Baxter Auto Parts for $45, including core charge. IPD sells this part for $132.92 (no core charge). Well, the master cylinder fixed the problem, and I now have a nice firm brake pedal and no brake failure warning light randomly turning on and off. Hooray!