1998 Ford Escort severe vibration from front of car

check the tyre pressures and try swapping the wheels front to back to see if this makes a difference,you say can`t find anything loose,have you checked lower arms,balljoints,bushes etc for excess play.check driveshafts and cv joints as well as engine and gearbox mounts are not split/damaged,make sure the wheel nuts are tight

Sounds like knackered wheel bearing .

could be a number of things but check the bottom arm bushes very common and easier to replace the whole arm than just the bushes but jack up one corner of the car ande get hold of the top and bottom of the wheel and check for any top and bottom movement and same side to side if there is top to bottom movement the can be three things bottom balll joint wheel bearing or even suspension top mount if there is side to side then its track rod ends that will need replacing and again wheel bearing cv joints is unlikely to be the problem here check the things i have mentioned should be able to solve the problem with these symtums your having

check your brakes .may be a seized caliper or or pad stuck or seized /bent slider