This has happened definately two, maybe three times, in the past year and randomly. I start the car, put it in drive and I have no brakes. One time I can remember it was after changing the brake pads so I figured I didn't pump it up properly and dismissed it. But the other time(s) the car was simply parked and I start it and nothing. Afterwords I pump, and switch the car on and off (don't know which of those actually fixed it) and all was good. This never happens when driving, master has all fluid, and no leaks under the car. Any thoughts besides the brake booster being bad?

This is crazy. This just happened to my wife's car last week. Still trying to figure this one out also. Her Mazda just one afternoon lost all pressure. I replaced the master cylinder and bled that, but still don't have any pressure. Trying to determine if its a ABS pump issue but been working on my car haven't had the time to work on her car yet.

So I finally had some time to work on the wife's Mazda. She had her brakes go spongy all of a sudden one day. I replaced the Master Cylinder 2 weeks ago and still no change. Over the weekend I just re-bled her brakes and her brake fluid was really dirty. I prob went thru 20oz of fresh fluid. I tried to flush out as much of the old fluid out. Once finished the brakes were back to normal. It's just strange that one day they would go spongy and lose the pressure. I was about to swap out the brake booster but good thing I tried to bleed the brakes again which solved this issue.

You still having this issue?