Checkt he Rotor Adjustment on the rotor. should be an allen key. I had a similar problem, and when I changed pads, I noticed the rotor had a lot of play in it, tightened down the allen nut or bolt or whatever you want to call it, and the rotor had less play and my brakes feel great.

I believe this is some kind of adjustment tot he rotor to remove play as it wears.

I am not sure on this, but pop off the wheel and look for the allen bolt to tighten down if it can be.

Could be something in the suspension like a worn bushing, but I'd say its either that adjustment, or a dirty sensor..

Could be warped slightly, but I would think that would be felt at any speed.

Alon

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'92 300CE - Sold
2004 C240 - 744 - C7 Wheels - Android Radio
2002 C320 - 816 - Sport Wagon - Sold
2006 E350 Wagon - 368 - Dead
2015 GL350 Bluetec - 197U