1. Purchase grease that is specifically labeled as wheel bearing grease.
2. Check the bearings you are going to pack. If it is a:
Tapered bearing – you will want the wider side facing down. This exposes the biggest opening in which to force the grease.
Roller Bearing – you will want the side with the thinner outer race facing down. This exposes the biggest opening in which to force the grease.
3. With your bearings sorted as to which side you will push the grease through now put a blob of grease on your palm toward the heel of your hand. The trick will be to scoop a little grease from the blob while pushing the bearing firmly against the heel of your hand to force the grease up and into the bearing.
4. Grasp the bearing in your other hand by hooking your index finger through the middle so you can get a good grip as things will soon become quite slippery. With the big opening facing down scoop a little grease from the blob while pushing the bearing firmly against the heel of your hand to force the grease up and into the bearing. After a few strokes in the same place you should start to see grease coming through the top.
5. As soon as you see the grease at the top, rotate the bearing a little and keep forcing the grease through. Every time you see the grease peek out, rotate the bearing again, until grease is peeking out all the way around.
At this point you are ready to install your newly packed wheel bearings.