The puzzler is about a car that idles rough at times. Turns out it was leaking brake fluid. The guys said something which surprised me. Maybe I misunderstood. But what I think I heard – as part of the explanation of the symptoms – is that it is possible for brake fluid to leak out of the master cylinder and into the power brake booster.
How is this possible? Isn’t the connection between the master cylinder and the power booster a simple mechanical one? In other words the driver pushes on the brake pedal, the vacuum in the power booster “gooses” the push rod input on the master cylinder with a little extra force is all. Or are there brake fluid containing tubes which connect these parts also? I just can’t imagine how brake fluid could get from the master cylinder to the power booster.