I used a kit from Brother on my 59'. It was complete with all the hardware, instruction were a little vague as you say. They do have a DIY link on their page, it has the Disc Brake kit there... I was just wondering if you seated the caliper bracket correctly, the pads should have some drag but not to the point that they won't turn... Have you measured the rotor with a micrometer and checked that measurement against the gap between the pads, that would be a starting point.
