You want to what? If you are going to re-pack bearings, you need to pull them out of the frame, with a bearing-puller, to avoid damaging the bearing (which still happens sometimes anyway). If the bearing is gritty and rough, it's already dead and you need to order new ones. You can get a little more life out of it by repacking at that point, but really just until the new ones come in, the tolerances have already been ground down and it's on it's last legs. To re-pack bearings, you have to pry off the dust seals and pass new grease through to purge the old grease out. This is a little delicate to get the seal off, with a dentist's pick or similar pry tool and then packing involves a ring of grease and pushing it against a surface like your hand, to purge to the other side. This can be good for some new bearings to keep water out, since they tend to come with much less grease for high rotation applications (which bike pivots are not).Reason is i wont to seal the all the pivot bearings with grease