G-Benz I had a similar experience with my brakes. My rears kept squeeling. I bought new rotors, new pads, even bought new pins and new backing spring and spent a beautiful afternoon changing the rear brakes. Used lots of paste and used regular OE pads. No DICE! Squeel returned. And I could have been at the beach.

By the way my rear brakes finally stopped squeeling after I bought wagner brake shims from www.********.com They cost $5. Wafer thin alloy shims that fit between the pads and inside caliper face. They also sell a front set.

I think the chronic squeel on W124's with correct OE/OE-like pads has to do with the age of the calipers, this is just a guess, my front ones use to squeel until I replaced them with rebuilt units.