Info re Wheel Bearing Greaser tool / Avensis 2001

[LezLezLez]

Hi, I have a lovely Toyota Avensis 2001 but there are first signs of minor wheel bearing rumble. I have discovered I can buy on eBay a "Wheel Bearing Greaser" tool which looks a good tool to use - grease gun operated. It will save removal of the pressed-in front bearings, not sure about the rear. Before starting with removal of the high-torque axle retention nuts can anyone support use of this tool? Also I assess my aperture at 46mm whereas the tools advertised only show 44mm. Can anyone confirm which is right please? Thank you in advance for your help. Geoff.