This is how you solve your issue. I had exactly the same issue when I replaced both my front callipers on my 13/60. Do it one side at a time. Remove both pads out of the calliper give the pedal a couple of pumps to get the pistons out of their normal position, and make the piston seal movement. Push both pistons back in replace pads and do the same on the other side. I guarantee that will fix the problem. The piston seals are dragging the piston back into the calliper and not allowing any movement
Andrew