[mikesz]

You don't say the year of your Boxster. The pre 2000 cars had an issue with water getting into the booster and rusting it out. Water would get into the rubber bellows between the bulkhead and the booster. I had this problem on my 99. You have to drain the brake fluid completely, remove the master cylinder and the booster. I chose to replace the booster and the master cylinder while I was in there. I also purchased the retro fit kit from Pelican so I wont have this problem again. I would say it is impossible to successfully do this without having the Porsche TSB and you must follow it step by step! also, instructions would have you replace the aluminum bar that connects the brake pedal to the booster. I did not do this there are ridges on both sides of the rod that the bellows fits into I got my dremel and machined the ridges off because the ridges are not needed with the retro kit. basically the retro kit isolates the brake pushrod from the bulkhead to the booster so no water will ever get in. I found my brakes locking up at red lights I have a tip and there was no creep found with an automatic. I disconnected the vacuum hose to the booster and stuck my finger in and found the water. PM me if I can be of any help.