Hello Gary,
I measured the nut and it was spot on 100mm so a tad under 4" but if a 4" fits then perhaps that's what I should be hunting for. Have a large open ended spanner which has been opened-out to suit but even with an offset in the handle, it clashes with the wheel studs so can't be used square-on so less than ideal.
Did wonder why the nut would be a metric size across the flats.
The hub on this Explorer (not my one) didn't need a puller as the nut had been loose and the whole lot nearly fell off with the wheel. Where it had been loose, the two keys had taken a bit of a battering so I've had to buy some key steel and make new ones.
I do have a home-made version of the original puller so hopefully will be useful.
Cheers
Mike.