I was just putting brakes together last night and had probably the same problem!! I was trying to do it with the caliper on there, so that the brakes didn't close up on me (which had happened before, ahha). I couldn't quite get the cover on all the way and it turned out that I just needed to remove that white plastic piece on the outside end of the working assembly inside the caliper, insert a flathead and turn until the little piston/screw thing on the opposite end came in a good ways, put the plastic piece back on, line it all up, and it went together no problem!! After I figured this part out, it was much easier to do off of the bike and I didn't have to worry about the piston closing up on me. Then I got it all hooked up and I had to press the brake lever down and release it a whole bunch of times until I didn't hear the ratcheting anymore. Now they work pissah!!