Drive the blind nut out of the firewall. Go to ACE Hardware and buy a 3' piece of allthread. They carry both standard and metric. Thread a new blind nut onto the end of the allthread. From inside the fuse, feed the allthread through the hole where the old blind nut was. Put a dab of epoxy on the blind nut flange. Now, put a washer and nut on the allthrtead spin it down to the firewall and tighten it to pull the blind nut into the firewall. When the glue dries, loosen the nut and spin the allthread out.

This is also a great way to install blind nuts in any hard to reach location.

Tony