It sounds like there is some other problem. Bleeding the brakes is not the solution. That is done when repairs result in having air in the system. The most common cause of this problem is improper bleeding procedures. Specifically, the brake pedal was pushed all the way to the floor. Crud and corrosion build up in the lower halves of the bores where the pistons in the master cylinder do not normally travel. Pushing the brake pedal over half way to the floor runs the rubber lip seals over that crud and can rip them. That results in a slowly-sinking brake pedal, and that often does not show up until two or three days later.
There is another problem that only applies to GM front-wheel-drive cars. There is a valve that trips in the master cylinder when unequal pressures build up in the two halves of the system. That valve prevents loss of brake fluid if there is a leak, and that is what happens when pedal-bleeding with a helper. That valve blocks fluid flow to one front wheel and the opposite rear wheel. That is what you have.
The only way I have ever found to reset that valve is to loosen the cap on the brake fluid reservoir, open the bleeder screw for one of the wheels that is not flowing any fluid, then give that bleeder screw a quick, short burst of compressed air. Do not go overboard. You would like to avoid pushing air all the way up to the master cylinder. Once the valve is unseated, just allow those two wheels to gravity-bleed. When the air bubbles stop appearing, close the bleeder screw, then push the brake pedal a few times, but never push it more than half way to the floor. Open each bleeder once more to expel the last few remaining air bubbles.
Friday, March 31st, 2017 AT 2:41 PM