Which parts fail
Components named in complaints (service brakes, ABS, rotors and pads, parking brake).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2008 Mazda CX-9 owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2008 Mazda CX-9. The contact stated while driving approximately 30 MPH, he noticed that the brakes felt loose and the braking distance had become extended while attempting to stop the vehicle. The contact stated that he heard a hissing sound while depressing the brake pedal. The contact stated no warning light was illuminated. The contact stated that the brakes failed completely while attempting to stop for a traffic signal and the vehicle rolled into the intersection. The contact had taken the vehicle to a local dealer, where it was diagnosed that the brake booster was malfunctionin,g and needed to be replaced. The vehicle had not been repaired. The manufacturer had not been informed of the failure. The failure mileage was approximately 115,000.
While driving the vehicle the brakes became hard to depress and a hissing came from my steering column, the car would not stop or respond to stop. I had to downshift to Neutral to get the speed slow enough to stop - and had passed through an intersection while in failure. I had also had symptoms I did not know at the time may be related which was at a stop at dunkins or a drive through at a stopped position - where the car would run rough the last few weeks. I thought the rough idle was gas related. I can no longer drive the vehicle and am told this is brake booster/pump issue / that other of the same parts in fords and other manufacturers are now extending customer sat programs like 13N02 because of faulty parts in the brake booster. the vehicle can be towed or seen for this problem. The vehicle has no existing coverage of the faulty brake booster. …
My wife was driving our CX-9 with our kids on Saturday when the brakes failed. This prevented her from braking at a red light. There were no dash warning lights prior to the incident. The brake fluid was at a recommended level since the vehicle is well maintained. We towed the vehicle to the local Mazda dealer (where we originally purchased the vehicle). On removal of the brake booster the Mazda dealership found the brake booster failed because it was full of brake fluid. On closer inspection they found the brake master cylinder was cracked which LED to the brake booster filling up and causing the brakes to fail. They said the brake master cylinder was not covered under the factory recall since this issue only happens to 2010-2011 model year CX-9's even though our 2008 CX-9 exhibits the same exact brake master cylinder defect. …
Tl* the contact owns a 2008 Mazda CX-9. The contact was driving 20 MPH when the brakes were depressed and the vehicle failed to stop properly, and crashed into a gate. The crash caused no injuries and the police were not contacted. The same failure recurred on multiple separate occasions and without warning. The vehicle was taken to the dealer where the dealer confirmed that both the master cylinder and power booster were leaking brake fluid and needed to be replaced. The manufacturer was contacted. The vehicle was repaired. The failure mileage was 68,000 and the current mileage was 68,200. Updated 04/26/12 according to the repair invoice, the brake booster was leaking due to corrosion from brake fluid leaking from the master cylinder into the booster. The brake master cylinder and booster were replaced. Updated 04/27/12
O was operating the vehicle and the brakes became spongy and failed to stop the vehicle unless I increased the effort to depress the brake pedal down. Foot has slipped on occasion causing my ankle to be struck on the pedal. I now down shift gears to slow the vehicle to assist in stopping while keeping even further back from vehicles in front of me. Currently, no recalls are out specifically for my VIN but the year make and model are consistent with the current recalls out for bad master brake cylinder and brake booster. Both of which have failed in my vehicle. I have contacted the gaithersburg md Mazda dealership and they insist the vehicle is not recalled and are suggesting I pay out of pocket for a known recall on these vehicles. Any assistance would be greatly appropriated. Thank you
While driving and coming to a stop, the brake pedal went real hard and car would not stop appropriately. This happened multiple times, checked the brake fluid is full as well as changed brakes themselves..problem still there and progressively worse, un drivable because of compromised braking. There is only 75K miles on this automobile. Having the car towed to local dealer, where I was told that Mazda has extended the warranty for braking system, which would take care of this problem as well as reimbursement for towing and expenses. This defect is very dangerouse, there was no warning, no warning light illuminated on the dash, I am very fortunate that this was caught before an accident occurred.
Tl* the contact owns a 2008 Mazda CX-9. While driving approximately 30 MPH, the vehicle hesitated to stop when the brake pedal was depressed. The vehicle was taken to an independent mechanic who stated that the brake boosters failed and were leaking brake fluid from the master cylinder. The contact researched online and found an extended warranty for the Mazda CX-9 vehicles. The dealer (morrie's inver grove Mazda, 10 mendota rd e, inver grove heights, mn 55077, [phone]) stated that there was an extended warranty specifically for the 2009 Mazda CX-9 models, but it had expired. The manufacturer was not contacted. The failure mileage was 156,000.
Tl* the contact owns a 2008 Mazda CX-9. While driving various speeds, the brake pedal became difficult to depress without warning. The contact stated that the brake pedal traveled to the floorboard before stopping the vehicle. The vehicle was taken to an independent mechanic where it was diagnosed that the electronic brake booster failed and needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure and informed the contact that the warranty had expired. The local dealer was not contacted. No further assistance was provided. The failure mileage was approximately 126,000. Repaired 10/10/17
Brake hissing from pedal area and brakes are very hard to press. Difficult to stop vehicle without applying lots of pedal force until a certain point where booster starts working and vehicle stops quickly. Dangerous at first because vehicle doesn't seem to stop without a great deal of pedal force then suddenly stops quickly after more pedal travel. Also, engine runs rough when hissing sound is heard- probably due to loss of vacuum. Problem is at all speeds. It takes a great deal of distance to stop at higher speeds for emergency braking (very dangerous).
Tl* the contact owns a 2008 Mazda CX-9. The contact stated that the brake pedal was difficult to depress. The contact had to shift the vehicle into park upon coming to a stop due to the failure. The contact also had to allow enough distance between other vehicles due to the brake pedal not completely stopping the vehicle. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 140,000.
NHTSA investigations
Brake master cylinder leak
The Office of Defects Investigation (ODI) opened PE11-026 to investigate possible brake performance loss due to brake fluid leaking from the master cylinder into the brake booster in model year (MY) 2008 Mazda CX-9 vehicles.In response to ODI's information request letter, Mazda identified a problem with the manufacturing process for the master cylinder primary plunger that could result in inappropriate surface…
Brake complaints in other CX-9 years
Frequently asked questions
How common are brake problems on the 2008 Mazda CX-9?
NHTSA has 30 complaints about the brakes of the 2008 Mazda CX-9, 17% of the model year's 172 complaints. The component named most often is foundation components › master cylinder (1 mentions).
Is there a recall for 2008 Mazda CX-9 brake problems?
No. NHTSA lists no brakes recall for the 2008 Mazda CX-9, though it has 5 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2008 Mazda CX-9 brake problems start?
Half of the complaints with a recorded mileage happened before about 78,000 miles, and 8% before 25,000 miles.
Is it dangerous?
Owners linked 2 crashes, 0 fires and 1 injury to brakes problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.