How do I remove and replace front wheel bearing on 1998 Mercury Mystique????

You'll need special tools to re seat the new races in the hub. The old races can be pushed out with a brass drift and a hammer. Same for the seal.

if it is a disc brake then the callipers would have had to be removed to get the hub off to replace the bearings
This would have possible dislodged the brake pad and it may have fallen out from being put in properly.
When putting the calliper back over the disc rotor it is easier to move the piston back if the bleeder nipple is opened so it is possible that the nipple was not tightened properly after assembly
remove the wheel and check that there is a pad either side of the disc rotor and that the nipple is tight

you will need a bearing press to change bearing or you can buy it as a compleat assembly below is a download of directions

It is a press in bearing . You will need about $600 in tools to get her done

Travis, this Mystique has sealed wheel bearings, you do not pack them with grease. You cannot even access the bearing. If you are not familiar with a car, you do not know if you are giving correct directions or not.

bearing in wheel more than likely faulty
solution jack car up and see is there play in wheel

you need to seat the bearings with ~ 60lbs of torque while spinning the rotor. Then back off the nut 1 flat ..

If you turn your steering wheel to the left as far as it can go and go to the FR (Front Right) tire you will be able to see it from there.

sounds like a wheel bearing gone bad

Hi, Front or rear???