Check the rivets that hold the coil bucket to the frame and the ones that hold the front cross member between the two frame rails.....The ones on my crossmember worked loose and I had to drill them out and replace with 7/16 bolts....I had the same noise recently on my left side, was going to drill out the coil bucket rivets and bolt it back on but all of a sudden the noise is gone..For now anyways..Oh BTW my truck is a 95 F150 4x4..
Hope that helps
check you're u-joints ,you did not say if you had automatic hubs if you do junkem they are nothing but a hassle. check to make sure all are well greased and the u-joints move freely and are not sloppy.check you're calipers and the two caliper pins,ford's are known for the caliper pins to wear out and cause a rattle in the front end . if left to long the caliper will rattle around and cause damage to the caliper and the knuckle. so for a little peace of mind every time you change front brakes put new caliper pins in as well. good luck.
If one's gone replace the other side as well, cheap insurance so to speak, as the other won't be far behind.
Hit Crappy Tire and get the Rockwell Joints - they have a lifetime warranty (they don't know what they're in for ) and the price is realtively the same. They'll replace them free if you bust them (Silly Monkey's :confused2 )