Eric2016

I was recently at the track and experienced something odd. While in the paddock, the brake pedal went to the floor with no resistance to speak of. After releasing the pedal, I then had brake pressure. It has been fine since. Mechanic could find no cause of this behavior. I've read things online that point toward the master cylinder as the likely culprit. Has anyone else experienced this issue?

JAhmed

Has never happened to me, at the track or otherwise. Odd. Did you just come off a session at the time?

ekam

You boiled your brake fluid. Do a flush and use higher boiling temp. fluids.

JAhmed

Just one pump with no pressure?

PorscheAddict

The only time I've had that happen is switching from full thickness track pads back to well-worn street pads. The pump or two of nothing but floor is to get the calipers to contact the pads, in that case. Never had it happen like you describe.

Eric2016

It was right after a session on track.

Voyager6

Not likely, but listen for a vacuum leak around the master cylinder to brake booster area. There is an o-ring on the MC there to seal and if it leaks, the pedal can go to the floor, but usually happens after the car has been sitting and the vacuum has bled off. If the leak is small, the running engine will overcome the leak and brakes are normal after the first press.

V6

85Gold

Not sure that’s correct. You would loose your assist but still have brake pedal. Without the engine running you still have brakes just a lot more effort required.

Peter

bernb6

Eric, if you came in directly from a hot lap with no cool down, that increases the possibility that the fluid boiled as the calipers soaked in the rotor heat. I boiled brake fluid twice on track in my 987.2 - in both cases, the brakes were notably soft afterwards, even after cooling. I strongly advise flushing your fluid. If the expelled fluid is deep honey color, then boiled fluid is likely. BTW, what fluid were you using?
Bern