Just FYI, unless someone wants to sell you a pin wrench they had made (or got from Crewe) because they no longer use it, it will probably be much less expensive to have one made. There are several threads on this forum where those of us who have done just that have posted photos of the variations on the theme that we've had custom made for us, and for very little money. See:
My custom accumulator pin wrench and holding jig for rebuilding SY accumulators.
There's not really much that's special about the accumulator control valves (ACV) as far as tooling goes. It's not difficult to get either a piece of bar-stock cut or an actual hex (male) socket to remove the end retaining cap on the ACV.
I have not, as yet, ever replaced the fluon pieces in the ACV as they've never needed it. See the image I included in
this post, as it's very instructive about what's inside the ACV.