I've just finished installing my new front disk brake rotors and I'm trying to get the grease cap seated. How do I do this? Every time I whack it with a mallot, it shifts over to one side and won't go in. This seems to be the toughest part of the whole job! Is there a special tool?

If you have a large socket that fits over the cap it works great.

you might also wipe the grease from the area around the inside of the hub where the cap goes in so the cap can "grab" the wall better and keep it from squirmming (sp?) around as much.

You just have to be careful not to remove too much grease or get any dirt / junk in the grease.