Brake failure

[mellon man]

Out for a Great Fun drive yesterday in my old trusty 1999 - 996 2.5 Boxster, but when I tried to stop at a red light the brake pedal was hard as rock and car just would not stop (very lucky nothing coming the other way frightened the s**t out of me though)

Drove very carefully there after, brakes were then sometimes OK sometimes hard but got home

Thank God safely.

Asked local Mechanic, who said it seems to be - because it was not happening all of the time it could be that there is some moisture in the Servo vacuum tube (and as the temperature was below freezing) and because it has such a long run from the engine in the back, to the servo pump in the front, the moisture could have frozen stopping the servo brake assistance pump from working.

Could this be the case or could it be something else? Any help and advice would be very much appreciated as I am now to scared (and as there is no warning) to use car in case it happens again.

[fpb111]

If your car is stored outdoors in the rain and the drains in the area under the battery/brake booster are clogged you can get water in the booster.

The booster on early cars (pre-2001?) has a vent in the bottom. When the tray under the booster fills with water the bottom of the booster is/can be under water. The water can get into the booster through that vent. If enough water gets in it can make it's way to the engine through the vacuum line and cause engine damage.

Later cars have the vent location moved away from the bottom.

Edited January 17, 2013 by fpb111