My wife and I took a ride up our local mountains to view a friends rental cabin. We went down a steep road for less than a 100 yards and our brakes went from very stiff or hard to spongy. I had to pump my brakes in order to stop and turn around. I thought I was losing my brakes but I was able to stop . I thought it was some type of anti skid or braking device. I didn't tell my wife at that time about my braking concern. We cancelled our visit and went home. We drove around 20 to 30 mph down the mountains and the braking didn't seem right but manageable. The following day there was a whistling or hissing sound from the brake booster and the brakes were hard to push. I had new brake pads put on our Mazda cx9 about 2 months ago and I've never heard of nor was I notified of a bad brake booster until I googled Mazda recalls. The recall was in 2014 and it addressed the 2009-2011 models. Ours is a 2013.

The brakes in my 2013 Mazda CX-9 have been making a hissing sound for several weeks, sometimes loudly. I started to notice the brakes were also hard to depress at times. I was sitting at an intersection with road construction and had to sit through several red lights, then the RPMs started to fluctuate and my car died. I was able to start it up again and when it was in park, the RPMs stopped fluctuating. The brakes are sketchy at best at this point and the car has died several more times.

I contacted the Mazda dealer and advised that this appears to be a known issue for CX-9s based on minimal internet research and they advised there is no known warranty extension or recall for brakes based on my VIN. I am getting the vehicle serviced next week so not sure if they will cover it or not.

I have begun to experience significant problems with the braking system on my 2013 Mazda Cx-9. When depressed, the brakes make a hissing sound and it is very difficult to depress the brake pedal. Had to pump the brake pedal extremely hard in order to slow the vehicle. Once depressed, there is a delay in bringing the vehicle to a stop, which poses a significant safety issue. It is almost as if power has been lost in the braking system.

Will take vehicle to the dealership tomorrow morning. It appears that the 2010, 2011, and 2012 models had the same problems. Why won't the manufacturer (Mazda) fix the brake problems on these vehicles or issue a recall......???