Brakes fail CC 2012 3.6L

[wideload]

Hello

Today I was driving when the brake pedal went to mush and basically went to the floor.
Braking was at maybe 10 to 20 percent. I parked it up for app 45min. I then drove home like nothing had ever happened.
It was suggested that it could be the master cylinder, one of the pistons is getting stuck.
Any ideas would be appreciated, and would it be safe to drive??

Thanks
George

[rjt86]

Were you giving your brakes a really hard time? If so the brake fluid could of boiled.

I would start by checking the fluid level to ensure there's no leaks, pretty sure the cc has a brake warning if he level gets low anyway. Haven't heard of a master cylinder failing but I guess it could be that also....

[Umai Naa!!]

I wouldn't be driving it.

Seems there may be some air in the lines that needs to be bled out.

Any warnign lights on the dash? Does the car run rough? If it does, it could be an issue with the booster.

[wideload]

No warning lights at all and no not giving it a hard time.
I will check the fluid levels.
thanks for the replies

[wideload]

I just went to check the level of the fluid, it seemed that the cap was loose. Could this cause the spongy pedal?

[Umai Naa!!]

No, because the system isn't pressurised at the reservoir.

If anything, it'll just let moisture into the brake fluid and contaminate it.

[3C4M Guy]

As Umai says, a loose cap will allow the brake fluid to absorb moisture. This in turn will lower the boiling point. But then you say you weren't using the brakes heavily.

You'd expect air bubbles in the fluid to give you a permanently spongy pedal rather than an intermittent one. When was the fluid last flushed and replaced? You could consider bleeding the system completely using fresh brake fluid paying particular attention to any bubbles that might come out with the old fluid. If no air bubbles, you can eliminate that as a cause.

Which then tends to bring you back to the previous suggestion of an intermittently faulty booster.

[Eaglen00b]

You haven't done any work underneath that could have possibly crimped/damaged lines? Long shot, I know.

[wideload]

Hello

Sorry for the late reply. No work was done to the car. Mechanic spoke to VW and they said they have never heard of an early replacement of the Master Cylinder, not common practice.
So a flush with new fluid and a bleed was done. So far so good.
Thanks to all for the replies.
George