2002 450 foreman ES front brake line question

I am trying to pinch the line off after the master cylinder to determine if my air leak is there or somewhere else. But when i go to pinch down on the flex house anywhere it seems like im gonna damage or crimp something off on the inside of the hose. I also wanted to pinch the house off at the wheel cylinders if i had to replace one to save the bleeding nightmare.

When you pinched the line. Was it hard? Did you have to use a lot of force or was it soft?

Well im trying not to drain the fluid if i dont have to. My brakes are loosing pressure i have to pump the lever to get any pressure then it goes away. So i am trying to pinch the line off after the master cylinder to see if i still loose pressure after i pump them up to see if its my master that needs to be rebuilt or something else like a cylinder. I cant see my line being full of anything i never lost any brake fluid. Just feels hard to pinch off for some reason

Ok here is exactly what is happening. When i squeeze my front brake lever it goes right to the handle bars. When i pump the lever i get brakes. As long as i have the lever squeezed the pressure stays strong. As soon as i release the lever and go to squeeze again it goes straight back to the handle bars. When i have the lever pumped up and the brakes are on i can squeeze hard for as long as i want and i dont loose any pressure. No
fluid is leaking from anywhere.

All my cylinders are clean and working good. My shoes have lots of pad and i just bled new fluid through the system. Zero air came out when i bled the new fluid through.