Problem with brake caliper or brake pump

[REBAcars]

Hey,

I have a big problem with my trackday car.
It has totally no braking power.
I have placed new brake lines.
Have put racing brake fluid in it and installed new brake pads.
But nothing of that seems to work.
There is also no air in the brake lines.
Wich makes me think there must be a problem with the brake pumps or the brake calipers.

How can i find out where the problem is?

car in question