I have a 2007 Mazda 3. When I purchased it, it came with a soft brake pedal. I thought that the brakes needed bleeding, but after taking it in to get it bled, there was no difference and apparently it needed a new master cylinder. They was going to charge me quite a lot, so I went a head and bought one and installed it myself which didn't take very long.

I filled it with brake fluid, and kinda bench pressed the master cylinder when it was already installed (an error on my part).

I then tried to bleed the brakes with very little fluid coming out. I understand that it may have a lot of air in the system and it may take a while, but I've tried and tried but still not a lot of brake fluid.

I'm not sure what I could do next but I'm stumped. Any advice?

Thank you!

  • Was the brake booster's vacuum line removed during the removal of the master cylinder and when you put the master cylinder on the vise, Did you fill the reservoir up, push on the plunger multiple times until fluid came out of all the holes ?
    – user38183
    Aug 3, 2019 at 11:51

2 Answers 2


I am not sure what you mean by "kinda bench pressed the master cylinder when it was already installed"

If you replaced the master cylinder, you should bleed each wheel starting with the wheel farthest from the master cylinder first. The key is to do it correctly by either using some kind of vacuum bleeding tool or having a helper pump the brakes for you while you loosen and tighten the bleeder valve.

Once you get the first wheel to flow bubble free, move on to the next one closer to the master cylinder. Make sure you keep the fluid in the reservoir topped off so you don't re-introduce any air by running out of fluid.

I am assuming you know how to properly bleed brakes manually. If that's not the case, you should look it up or open another question.

  • I took out the master cylinder and bench pressed it today. No air inside at all. Put it back on, and bled the brakes from the further from the master cylinder to the closest. I've spend hours and theirs literally no difference. I have no idea what the problem could be...
    – Jonathon
    Mar 7, 2019 at 21:15
  • If you are getting air coming out of the bleeder valves, there has to be a leak somewhere. Mar 11, 2019 at 23:36

I'm assuming that you've already changed your brake pads or they're still good?

There are a couple of different issues that could be happening. First,check for any fluid line leaks. You can check this by looking around the brake lines and the brake system components for any dark rust or darker than normal rubber. It's very interesting that you can't seem to get fluid out of system when you bleed.

I do also know that Ford and Mazda collaborated and shared a lot of technology when they made your car, and the Ford Fusions of that generation have issues with a ABS valve staying open and reducing the hydraulic pressure available, so you might want to check that with your mechanic.

Hope this helps!

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