Originally Posted by marsdog
You mean leave the master cylinder reservoir open during bleeding? No, I did put the cap back (to avoid squirting fluid, I read somewhere) but disconnected the cable goes into the cap (not sure what that is for). How did this hurt the master cylinder?
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.