bleed brakes after you replace the front calipers

Here is a video and guide below to help you bleed the brake system correctly.

https://youtu.be/w7gUsj2us0U

and

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

and

https://youtu.be/WDxvEQrMkBg

Please run down these guides and report back.

The best is to open both bleeder screws and crack the cover of the master cylinder so it won't build up a vacuum as the fluid leaves. Wait for fluid to gravity-bleed, close the bleeders, work the brake pedal a little by hand, then open the bleeders once more to let the last few air bubbles out. You might have to stroke the pedal a little to get the fluid started if you let the reservoir run empty.

Some people like to have a helper push the brake pedal but if you do it that way, be sure to never allow the pedal to go more than half way to the floor. Crud and corrosion build up in the lower halves of the two bores where the pistons don't normally travel. Running the pedal to the floor can rip the internal lip seals on that corrosion.

You're going to have to pump the pistons out of the calipers until the pads contact the rotors. Until that happens you will also be able to push the pedal more than half way. Be careful to just keep pumping it only half way until it gets firm.