American Motors: brake bleeding, brake hoses, proportion valve

Question
explain to me how changing brake hoses will help
-------------------------------------------
The text above is a follow-up to ...

-----Question-----
1984 CJ-7 with manual brakes disk front and drum rear
-------------------------------------------
The text above is a follow-up to ...

-----Question-----
I changed out both front and rear brakes, calipers and rear brake cylinders. I bled the system now the front brakes drag. I adjusted the rear drums and the front disk brakes still drag. I was told that maybe I have to hold the pin in the proportion valve when bleeding them? is that right?
-----Answer-----
YEAR and MODEL ?.
-----Answer-----
Replace BOTH front and the one rear rubber brake hoses.  

Answer
Over time the brake hoses collapse inside and naturally when you apply the brakes there is a tremendous amount of pressure to push the brake fluid thru the brake hose to the caliper to stop the vehicle.

However, there is NO PRESSURE to force the brake fluid back up thru the brake hose to the master cylinder, Thus the brakes will remain applied due to the internal collapse of the brake hoses.