I've got a buddy who's working on a OT pickup that is a body-off restomod of sorts. He hasn't cut any corners and he's coming close to having it ready for final assembly...but has ran in to a wall with his brakes. It's a Chevy Pickup that would have had four wheel drum brakes when it was new. He has converted it to 4 wheel discs. Every single part of his system is new. Calipers, soft lines, hard lines, booster, master cylinder...everything is new and was intended to be used for this conversion. The problem is he can't get it to build up a pedal. This is where it gets strange ( I guess you could say it's strange ). He can take a rag and a pair of vise grips and clamp off his soft brake line in between the frame and the rearend and he's got great pedal. You'd think that this would indicate air in the lines at some point between there and the rear calipers...But no matter how many times he's bled them he gets nothing but fluid. He can remove the vise grips from that line and put a pair on both soft lines that go from the rearend to the calipers and have great pedal....Still can't get anything but fluid to come out of the bleeder valves. He's had two different mechanics ( both of whom actually put bread on the table working on cars) come over and look at it and tell him that they've got no idea what's wrong with it. In the meantime in an effort to locate a possible defective part of the system, he's replaced the master cylinder (twice), the proportioning valve, and the rear calipers. He's tried cracking open and bleeding the hard lines at every joint between the front and back of the truck. He's unbolted the rear calipers and tilted them so that the bleeder valves would point straight up and made sure they were full of fluid by injecting them with a syringe. What's being overlooked here? The rod that goes from the brake pedal to the booster was also replaced during all of this. Is it possible that it could be to short or to long? Would that have anything at all to do with the problem that he's fighting with? At this point any and all advice and suggestions would be appreciated. Thanks!