Those are Huck brakes. Here is a diagramn of the assembly.
Brake Diagram You need to remove the clip, designated as 5.057 on the diagram. It is behind on the back end of the pin at the bottom. There is a wide area on the clip that you bend up and then you can slip the clip off the pin. The other two pins are fastened the same one. Be really careful with the clips because they are hard to find new.
