The rotors on the front of a Mustang are held in place by the rims and lug nuts. When the tires were replaced some dirt/crap got between the rotor and hub. This makes it act as if the rotor is warped. And it will become warped if left like that. Best fix is to remove the wheels, brake calipers (Don't take the hose off the caliper(s) or you'll have to bleed the lines), and rotors. Clean EVERYTHING with brake cleaner, nothing else! Reassemble being careful to seat the rotors fully against the hubs. Best way to do this is by installing 2 lug nuts (by hand wrench only) with the flare out, then put the retainers (the little flat washers with the tabs on the inside diameter) on 2 other studs to hold the rotor in place. Remove the 2 lug nuts and replace the wheel, install the lug nuts, and torque them correctly.
I've also been told that on ANY car that has rotors mounted like this it is best to NEVER use any kind of powered impact wrench to install the front lug nuts. This alone can mis-seat the rotors, or even make them slightly out of round, which because of the Mustangs' sensitive steering, you will feel as vibration when applying the brakes.
Hope this VERY long note helps.
Saturday, August 13th, 2011 AT 1:59 AM