I am writing with frustration in regards to my Mazda CX9 grand touring car which we purchased used in 2015 with 72,000 now at 93,000 miles (VIN JM3TB3DV7B0319372) It is used as a family car taking our two kids to school and family trips. I have just driven back to Boston from a family vacation in Washington DC luckily with no issues . Now we are suddenly having braking issues. I was a mechanic for 14 years and self-diagnosed the problem immediately as a brake booster problem, and the master cylinder is failing too, characterized by the hard brake pedal and slow creeping when pressed hard plus low fluid. After doing a quick search to see if this was known problem I was shocked to realize this has been an ongoing problem with this model for a number of years with no recall issued, which I find surprising when families are being put at risk. I did find that the company offered an extended warranty on the brake system for 7 years or 90,000 miles whichever came first. We are now outside this window, having purchased the car used and not knowing there was a serious problem till it became apparent while driving. I was driving in Boston where I live and I suddenly found I had a very heavy brake pedal and was not stopping safely. Thankfully I was on my own at the time and with my knowledge of cars was able use excessive foot pressure to brake in time. As a used owner I’m frustrated as there seems no support for customers who purchased these cars used and are unaware their car is not safe and can fail at 50,000, 70,000 or 90,000. I’m now faced with a very expensive repair which should still be covered by the manufacturer’s commitment to quality and the used car market. Having been a mechanic for numerous years I find it shocking a car of just over 5 years is having major braking problems, and Mazda is not showing enough commitment to fixing thee issues. I assume its totally based on there not being enough complaints made and the issue not being very public. Eventually someone will crash and this will be a blight on the company who’s cars I have enjoyed driving but when the public are put at risk. It’s disheartening to know the Mazda doesn’t step up.