I have a Kent adult tricycle. It has a band brake attached to the rear axle. The brake pad is old and no longer grips, so I need to replace it. Apparently I can't just replace the pad because it is riveted to the whole brake assembly. So I have to replace the whole brake assembly. The brake assembly is fixed around the axle, and to remove it I have to first remove the whole axle.

My problem is two wire pins that hold the axle in place. I call them pins but they are actually a length of wire, doubled up and inserted through a hole in the axle, with the loose ends wrapped around the axle. I don't know what tools I should use to remove them, or what tools I will need to put them back in place afterwards, or if I need to buy new pins, or even what they're called. There is little space to work in. See the picture below.

Here's a closeup of the brake-side pin. This one is particularly tricky because the brake housing is attached to the frame very close to it, and there isn't quite enough room to unscrew the brake housing from the frame (there's a hex screw on the inside of the brake housing). I can't unscrew the brake housing until I first get rid of the rear sprockets to make more room to fit my hex wrench, which I can't do until I've removed the axle.

So, how do I remove and replace these pins, and what are they called?