1991 Corvette convertable. New brakes, new fluid adjusted and bled but once car get warm after an hour or so the brake pedal goes almost to the floor. If you let the car cool off, the brakes work just fine. The Chevy dealer can find no issues and no codes are evident. The dealer doesn't allow the car to get warm enough to experience the problem! : Cry:
Best guess. When the brake fluid gets warm during use the viscosity of fuild thins. Or can even boil. If the system was not bleed properly. Or enought fluid added. Or the wong dot fluid used. May be the cause of the problem. Also make sure that the master cyclinder was not replace. If the it was. A rebuilt master cyclinder or the wrong master cyclinder may have been used. One other source may be a vacum leak or air leak on the brake booster. If the master cyclinder was leaking the fluid can cause the brake booster seals to leak. Causing brake fading. Please have some one check these ideas. Brakes are not something to take lighty. Your life or someone eles may be at stake.