I was reading an article on changing wheel bearings. I have a tip for you. Normally, the original bearing is the type you have to pack with grease and seal to keep out the road much. This is usually aging and, probably, leaking. Of course, we all go mad with the pressure-washer, and water gets into the bearing.

Sometimes, the bearings are type SS (steel seal), which isn't much use to keep out water. When I replace bearings on my motorcycles, I use RS (rubber seal) bearings. Use this type and get a good brand. This type of bearings has its own lip seal, plus the seal you already have on the wheel, so there's far less chance of dirt and water ingress. You just have to make sure the seal it isn't damaged when fitting it.

I've only done this once and I used a piece of 3/8 steel bar with a nice flat end. It is small enough to fit "across" the inside of the spacer and catch the edge of the bearing's inner race. Using the largest hammer you have keep tension on the exposed bit of the steel bar and just tap firmly one side then flip the steel bar to the the other side and repeat. Eventually the bearing will start to move once it does just continue to alternate one side to the other until the bearing falls out. After removing the central spacer the other bearing is easier.

Refitting the new bearings? Just pop them in the freezer for a while and it will be easier to install. They might simply just drop in. If not tap them in using a piece of wood as protection from the hammer!