I went through the same thing with mine. In my case I had converted to a dual master cylinder. They seemed soft and I would pump it a couple times and it would get firmer. I still had some air left in the system, but the shoes were not adjusted tight enough yet either. To make sure there was no more air, I would have someone pump about 10 times real fast and hold the pedal down at the end of the pumps. Then I would crack the bleeder screw with a hose and bottle attached. When there was no mroe bubbly fluid coming out, I knew the air was out. I started with the left rear, then right rear, then right front, then left front. Then I jacked up each corner of the truck and adjusted the shoes again. There is a really faint drag now when you turn the wheels. They are firm now and stop the truck. I took a bunch of pictures through the whole process and they are on the "brakes" section of my webshots. Hope this helps someone cause it sure drove me nuts for a week or two.
