I had a problem like this years ago and it was a combination of a bad tire
and a bad wheel bearing.
And a totally worn out front end...
IMHO, you may want to get her off the floor and shake down the whole works...
(front end parts, wheel bearings...) plus check your tire pressures and rotate your
tires to check for a broken chord, missing wheel weight, etc.
Are the rotors new? Were they turned prior to install?
... my 2 cents...
