HI I know how to bleed brakes but how about when the brake levers are in and the system is dry? Is there a spring that pushes the plunger out ?

Man this 96 / 6×6 sure has been neglected. I knew the bleed screw was going to come out hard so I heated it with a torch and it broke anyhow. I sprayed them with pb blaster and let set overnight too. Should I try to replace it or just leave it and use the line as a bleed.

thanks KK4