Power Steering issues after rebuild

the pump valve seemed free when i installed it, i pushed the seal back into place re-filled the system and no pump noise and the power steering worked. i know this is not a true fix but as soon as i put pressure on it the seal blew out again. So now i'm going to change the seal out and disassemble the pump to check the valve, not sure about the box top yet. i want to start with the things i touched last first if you know what i mean. i have another box but it is for a 73 and up. i also have the pitman arm, idler arm but i'm missing the center link for that change out if the box is my problem.