The wheel bearings on your MG are very rugged bits of machinery, and when treated properly will generally have a very long life. When they do fail it is almost always because of lack of lubrication (neglect) or from contamination (bad seals allow water to enter and rust the bearing races).

To my great surprise, the factory workshop manual does not call for periodic maintenance of the wheel bearings. What it does say is the following: "As far as possible, bearings which come under review during the overhaul of the car should be cleaned and inspected without being withdrawn from the housings to which they are fitted". I guess that begs the question, how often do you overhaul your car? And it goes on to mention possible deterioration to the housings caused by unnecessary withdrawal.

I do periodically remove the bearings from the hubs for cleaning and inspection and repacking. Maybe they have a point though, because I did once have to replace one of the front hubs when it became worn such that one of the larger inner bearings was a bit lose. This one was no longer a press fit in the housing but could drop out by gravity when the hub was up-ended. I also replaced one for a friend once because of the same problem. So far used hubs are still pretty cheap, so I figure it's not a bad tradeoff to change one at 1/4 million miles in order to allow the periodic removal of the bearings for servicing. But if you have access to a pressurized parts washer and can manage to clean and relube the bearings without removing them, I wouldn't complain.

For more general information on rolling element bearings, nature, inspection, and replacement, check under MG Universal Tech.

When it comes to repacking the bearing you can use any resource at hand, including your hands, to force grease into one side of the bearing until it comes out the other side. There are special tools for this that can be used with a grease gun, but for infrequent use the tool cleanup time might be more of a bother than packing by hand. The original bearings were open on both sides, easy to clean and easy to repack.

For removing the hub and bearings, they usually come off the spindle with a reasonably moderate tug, often by hand pull or gentle dead blow hammer tap, otherwise a few yanks on a slide hammer (pulls anything) puller. If it is tight enough to give trouble with a slide hammer you may need a torch, and all bets are off for saving the parts. The most common reason they seize solid is because the nut was not tight enough the last time, the bearings were allowed to run dry, and the inner race either heated or spun on the spindle.