water logged brake booster

[mikesz]

I am in the process of replacing the brake booster in my 99 Boxster. while I am at it going to replace the master cylinder, paint the calipers, and flush the brake fluid. Pads, rotors, sensors are all new already. The brake booster has water in it. when i removed the vacuum line and stuck my finger in about half inch below opening i can feel water. also as i was depressing the pedal to get all fluid out I could hear the water.

the question i have is how does the water get in to the booster in the first place?
I am replacing the booster with a new one and dont want to have this problem again if possible so can i prevent this from happening again?

I have had the car since february it has 75k on it. Since I have owned it it has been garaged but I do wash it often and figure that is where the water came from. I have never heard of anything like this with any other car.