I have a 2023 CX9 TP with 18k. Noticed the brake pedal starting to get lower and needing to pump them to get the pedal higher. Took it to my Mazda dealer on 2/11 and they took two weeks and replaced the master cylinder. Pick it up and the problem is worse. Pedal goes almost to the floor. After waiting another 8 weeks, go to pick it up today (4/23) and get in, hit the brakes and the pedal sinks to the floor again. Service advisor gets in and agrees they are not working. Back in the loaner. Anyone here had any similar brake issue?
Brake pedal low
- Thread starter r2rickster
- Start date
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- 2016 Mazda CX-9
I have a 2016 CX9 GT, and I never had this sort of issue. Granted, it does take me to push the brake pedal further than in other vehicles I own (Ford, Volvo, and Hyundai). However, with that being said, some of the possible causes that I can think of could be:
If I were you, I would return to the Mazda dealership, ask to speak with the service manager, and request the necessary documentation. Ask the service manager for a full write-up of what was done so far, including part numbers and bleed procedures. Then ask if ABS bleeding was done; if not, that might be the root cause.
Finally, after getting all the documentation from the dealership that originally did the work, I'd probably consider another dealer or a third-party mechanic that specializes in Mazda vehicles. If the original dealer has had 10+ weeks and failed twice, another Mazda-certified shop may offer better diagnostics.
- Shawnee
- Air in the Brake Lines - After replacing the master cylinder, the system needs to be properly bled. If air is trapped, the pedal will feel soft or sink to the floor.
- Faulty Master Cylinder (Again) - It’s possible that the replacement part was defective or not installed correctly.
- Brake Fluid Leak - Could be at a line, caliper, ABS module, or a connection. A visual inspection underneath the car and around the wheels would show leaks.
- ABS Module Issues - Some modern ABS systems require specific scan tools to bleed and calibrate properly. If the dealer didn’t do this, it could explain the soft pedal.
- Brake Booster or Vacuum Leak - Although less common, a failing brake booster or vacuum issue can also cause poor pedal response.
If I were you, I would return to the Mazda dealership, ask to speak with the service manager, and request the necessary documentation. Ask the service manager for a full write-up of what was done so far, including part numbers and bleed procedures. Then ask if ABS bleeding was done; if not, that might be the root cause.
Finally, after getting all the documentation from the dealership that originally did the work, I'd probably consider another dealer or a third-party mechanic that specializes in Mazda vehicles. If the original dealer has had 10+ weeks and failed twice, another Mazda-certified shop may offer better diagnostics.
- Shawnee
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- Canada
Yes I have emailed them explaining the situation. Waiting on a reply. Thanks
I agree with all of your suggestions. You would think a certified Mazda mechanic at a dealership would know these things. I even know these things and actually asked them about them. The service dept. says that they are in touch with Mazda and can only do what steps Mazda tells them to follow under warranty.
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- Mazda CX-9 Signature
Let them know it's a safety issue. If they can't properly diagnose and resolve, then you need to escalate and report it to NHTSA (assuming you're in the US)
Update. Mazda sent their area tech to the dealer and now they are going to replace the ABS unit. Going to be another two weeks. Told them when it's done, I want the area tech to go back and sign off that it is fixed. Not the mechanics who already told me twice it was fixed.
