I found this thread v. useful since I too found my small, outer, unsealed needle cage all rusted up just like the pictures shown. Greasing it at every tyre change is a "must" from now on!
So armed with this info I bought myself a slide hammer bearing puller (only £35 from Amazon), a new needle bearing and inner race and a canister of freeze release. I did try "wacking" the back of the bearing to drive it out from the other side using a thick steel rod before I realised that I was just hitting a thick steel washer that the bearing is squashed against that appears to be trapped in by a steel cylinder that lines the surface into which the bearing is inserted So at this point I looked at this thread and got myself properly prepared. I levered out the inner cage and needles with a screwdriver to give me a surface to pull against. I heated up the bevel box first by just setting it close to domestic room heating electric fan. The bevel box was still filled with oil. Using my meter that has a thermocouple and a setting to read its temperature, this showed that I got the whole box to about 45-50deg.C. I then inserted my 30mm puller and expanded it to catch the outer lip of the bearing and I squirted some of the freeze/light oil release (though I'm not really convinced that this actually did anything). I then spent about 10-15 minutes playing my hot-air gun around the needle bearing, monitoring the surface temperature until it got up to 100deg.C, and then used the slide hammer. It did pull the bearing up about 4mm before the outer lip distorted, expanding just enough to allow the puller to detach. Now that there was a gap at the back I then re-seated it against the back face, tightened it up, gave it another freeze spray and reheated it back up to 100deg.C and then with about 5 or 6 modest slide-hammer wacks it came out. I am now just carefully contemplating how I can pull in the new bearing with a bolt down the central axle hole after, heating it up to what appears to be an obligatory 100deg.C.
Any good thoughts or things I should be careful of here?