i initially posted this in Repair Q&A, then realised that this was probably the best place.
I just picked up a Wyvern 101, which can be seen here http://www.fountainp...879-wyvern-101/
but the sac was perished. It is a button filler and I was wondering whether the brass button section needs to be pulled out the same as a Duofold button filler in order to embed the pressure bar. Any advice would be gratefully accepted.