To eliminate squeel... remove pads... take hack saw and cut down the length of the pad in the center to a debth of 1/2 the thickness. Then file off the top and bottom edges of the pad so that there is no right angled edge. reinsert pads and they will not squeel. What you will have done is to eliminate the reason the pads were vibrating. All other cures are only temporary.
1993 190E 2.3
2000 Toyota 4x4 Tundra