I have an '86 K5 with power brakes. I recently replaced the master cylinder, front calipers and did the disk conversion on the 14bff rear. I used the Dana 44 disks and calipers on the rear. My problem is that when the truck is off the pedal is very firm...but when I start the truck the pedal goes to the floor. Its not a bleeding problem...trust me ..I have bled the master and all the calipers to the tune of 4 quarts of fluid. Does anyone have any better ideas than taking it to a shop?