Originally Posted by whynotthinkwhynot
Brake fluid does not compress. So if you put the cap back on, then you have someone open up a bleeder, push fluid out, tighten the bleeder, and then let up on the pedal, things can break. AFAIK, there is not a design that overcomes this basic principle, but you might get lucky and it's just air in the system. A vacuum bleeder will set you straight. If you can get a hard pedal again- then you're ok. If not then you need to replace the master cylinder and be sure to follow the bench bleeding process, then vacuum bleed again.
Thanks. Will try the vacuum bleeder. "Mity Vac MV8020 Brake Bleeding Kit" is what you referred to, right?
I drove 30+ miles with the soft pedal this afternoon and it was not that bad. Any other sign I can tell if the master cylinder is broken, e.g. fluid leak after driving?