Ihad squeeling brakes when I first got my car. I found that the disc was actually loose. I tightened it down with the little allen bolt, and it stopped the squeek.
I too thought that I had the ABS kicking in. After I made the adjustment, the cars braking was much smoother.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.