I have a 97 grand marquis and every time I break my front end shakes but my breaks and rotors are good

Ok, I believe you..... must have some reason to say the rotors are good. But how do you know? Are they new? Been re-surfaced lately? How many miles on brakes? The reason I ask is the is the first thing comes to mind on that question-- A warped rotor. Can you feel it in the steering wheel? Or please describe the 'shake' in as much detail as possible. The next item is a suspension problem. Shocks/struts, tie-rods, etc.

"Shake and brake" is a common problem. Warped rotors are the most common cause of this. Overtightening the lug nuts is the most common cause of warped rotors. A warped rotor can look brand new, but still be warped. My bet is that the rotor or rotors are warped. This has nothing to do with the condition of the brake pads.

I replaced mine with drilled and slotted ones from RockAuto. Way better than factory ones. no more shake.

Drilled rotors look cool, but they can crack at the holes. I don't recommend them for the street.

You also my want to check your guide pins on your calipers I had the same problem not to long ago with my wife's car. They might need cleaned up and lubed up.