You need to clean out any old grease in the hubs before you apply new grease and the bearings. A good - and cheap - solvent is charcoal-lighter fluid. Do this outdoors or a well-ventilated space. Once the hub is nice and clean, examine the cups & cones for any signs if pitting. Make a mental note of your findings - this is what you want to find the next time you overhaul the hubs. Then proceed with re-packing and adjusting them.