brake problem

[firsttimeowner]

Lat year bought a 1981 911 from a dealer which had purchased the car and refurbished it which included ensuring the brakes and associated parts were all fine. drove it last summer no problems. had it inspected this spring and all fine. drove it this summer about once a week. last time I drove it after it had sat about one week, I went about 10 miles with no problems when suddenly I had no breaks. brakes returned after pumping but each time I braked for the first time, went to the floor before they came back. then the brake light came on. kept going on back roads and after about 10 minutes, the brake light went off and the brakes worked normally. took it to a trustworthy garage and they could fine nothing wrong. linings fine, etc. I am reluctant to drive it as this problem previously occurred with no warning. I am not mechanically savvy but will take any suggestions back to the garage with the car. any ideas of what we can do or can this happen once and never again?

[Eric 3566]

Hi from my experience sounds like the master cylinder might be going out. If you have covered the basics making sure that the system has been bled and has fluid and is not leaking fluid anywhere. The good test is to pump the brake pedal 5 or 6 times and hold pressure on the paddle with your foot for sometimes up to you 60 seconds or so you will feel the pedals start to go down on a sudden that would be a bad master cylinder. It's good to Paris on the paddle pretty hard sometimes longer in 60 seconds maybe a couple of minutes this is a good field test good luck