some things you could check; is the caliper not bolted tightly to the steering knuckle? Is the hub nut tight? Are the lug nuts for the wheel all snug?
If there is a griding noise, it should result in some evidence of metal-to-metal scraping. By removing each front wheel, you can look on the inside of the rim, to see if the caliper has been rubbing on the inner part of the wheel.
And the old standby test.... With a front wheel jacked up off the ground, see if you can wiggle it. Grab it with two hands at the noon and 6 p.m. parts, and see if the wheel will move at all. Then do it with two hands, at 3 p.m. and 9 a.m. positions. There might be some movement, but it should Only be due to the steering wheel turning as you try to turn the wheel left-right.
Also have a look on the strut, where it runs near the tire. A broken strut may not be obvious.