05 Cayenne stiff hard brake pedal

[05 Cayenne]

Hello,
We changed the brakes on my 05 Cayenne base model. And after it was done, the brake pedal was very stiff/hard to push in (stays at the top) and could not stop the car as normally it would.*We bled the brakes to see if that was the problem, but still the same. I read somewhere its possibly the brake booster/sensor, but how could that be the case, we did nothing but just change the brakes.**Any insight and experience would be very helpful at this point before I start spending more money when I don’t need to.*
Thanks

[Bunka]

More info please. Changed the brakes? Rotors? Pads? Pad wear sensors? Caliper bolts? Front only? Rear only? Both front and rear? Did you get a free flow of fluid at each wheel when you bled them? Are you sure any added brake fluid is compatible with the old fluid? Were all the bolts torqued to the proper specs?

Were the new brakes sourced from a knowledgeable Porsche supply shop? On the surface, it sounds like one or more obstructions. I would double check the part numbers to make sure they gave you the correct parts. Measure the rotor diameter to make sure they are the same as old. If you disconnect each brake line you can check to make sure that the fluid is freely flowing. If not the obstruction is in the brake line, master cylinder, or the mechanical part of the brake pedal. If there is a free flow of fluid at all four wheels then the obstruction is in one or more caliper assemblies. During the same model year, Porsche used different brake assemblies, depending on sub model and/or performance options.

Brakes are synergistic assemblies. The final outcome depend entirely on the sum of all the parts.