Brake line resitricion

[geunther]

Short: Should the rear flexible drop down line with T block offer any restriction?

Long: I know any designed in restriction should be handled by the proportioning valve. I flushed out my rear lines starting at the proportioning valve (pv). When I had the butt connection inside the frame rail (near the rear axle) disconnected, air would blow freely from the pv to the junction. When I had the butt connection connected, there was some back pressure when blowing in at the pv. Wheel lines were disconnected so any change in restriction would have been from the drop down line, or the line between the drop down line and the butt connection.

I wold still get flow at the T block (wheel lines disconnected). The flow seemed to be restricted either within the flexible line or due to the size of the T block orifices. Im just not sure if this is normal or air should flow freely from the pv all the way to the wheel cylinders.