The brake fluid is full but the brake pedal goes to the floor

Hello,

Besides having low fluid, the brake pedal can go to the floor for having air in the brake lines, leak in the system or a faulty master cylinder.

https://www.2carpros.com/articles/brake-pedal-goes-to-the-floor

First make sure there are no leak in the brake system. Inspect the hoses and lines, check the brake calipers for leaks.
Next step would be to bleed the brake system. This will purge out any air that might have been trapped inside.

Here is a helpful guide on how to bleed the brakes:

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system

After bleeding the system, if the issue still exists then it is likely a faulty master cylinder and need to be replaced.

https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder

I have attached the instruction of brake bleeding and master cylinder replacement and adjustment procedures below.

Please let me know if you have any questions.
Thank you.