Some Filofaxes have replaceable rings – some older ones as well as Ostrich and (as far as I know) Lizard. The rings are fairly simple to change. I have done one for someone else and two of my own.
You remove the defective rings, leaving just the backplate. Then you slot the new rings onto the backplate and voila!
With the high rate of ring problems that occur on Filofaxes and Gillios it is so nice to be able to change the rings and continue to the use the binder. On binders with non-replaceable ring systems, if the rings go the binder is useless.
Here is a video by Tom of Gillio showing how it is done