Bleeding brakes

If the brake lines that were connected to the master cylinder got any air in them while the new one was being installed then you will need to bleed the brakes at each wheel as well.

How to bleed the brakes at the wheels : https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system

And here is more basic information on soft brake pedal and pedals that go to the floor: https://www.2carpros.com/articles/brake-pedal-goes-to-the-floor

Check those articles out, and then try bleeding the brakes at the wheels. If that does not work, then it is possible that you simply got a bad master cylinder.

Okay, thank you. I did not even think about the lines. About how many times would I need to bleed each wheel?

I usually do each wheel three times, pumping the pedal fifteen times with each iteration, and then it is good. Then I do it a fourth time for good measure.

I bled each brake and after doing so the brakes were still the same, the pedal sunk to the floor with no resistance. Before I bought another master cylinder I thought I would test it. So I disconnected the brake lines and shut the holes were they connect to the master cylinder, it felt like it should, like a normal brake pedal. So I figure it is somewhere else in my brakes. I should also mention I just installed brand new calipers in the front, would there be something wrong with them? Thank you.

If there were something going on with the new calipers, it would be due to a leak. You would see the brake fluid leaking out of them without a doubt. The only other thing I can think of is simply that you got a dud of a master cylinder. One or more of the internal seals is allowing fluid to flow by. You would not necessarily know it by simply pushing on the push-rod. Believe it or not, with aftermarket and re-manufactured master cylinders, this happens more than you would believe.

You can also check out this guide: https://www.2carpros.com/articles/brake-pedal-goes-to-the-floor

Go through it and see if it helps you out.

Well dang, I was hoping that was not the case. Thank you for the help, I greatly appreciate it. I did not know these things were so prone to go bad.

Use 2CarPros anytime, we are here to help. Please tell a friend.

Cheers, Ken