How to replace rear brake cable on 1990's GT Tequesta?

[Sham69]

For sake of completion...

In the end I fashioned a wedge-shaped square aluminium washer that I placed between brake arm and block which allowed the block to sit flat against the rim, more or less.

Many thanks for your contributions.

 

[DRM]

Leave inner in place, slide out the outer. Slide a new outer on over the old inner. May take some wiggling at the other end, but it will go.

With the new outer in place you can then release and replace the inner.

This ^^^^^