Car Shimmy when braking at high speeds

my 1998 ford expedition shimmys when braking at high speeds. Any thoughts why and how much it might cost to fix?

The front brake rotors are probably warped. Check for the best price for front brake service.

Tester

Have the rotors check for run-out (warpage) I things are in spec (run-out not so great, overall thickness after turning in spec just have the rotots turned. Then you can give a thought about brake pads maybe you want a pad with a different compostion and you will change pads even if not required due to thickness.Personally I would not hesitate a second to change pads no matter what their condition (OK just replaced is another story) I have seen alot of pads changed without rotor turning with mixed results. For a shop they probably wouldnt go for rotor turning without pad replacement. But for the DIY no safety issue but setting your self up for poor results and wasted time