My 1994 E420 has been plagued with the most unbelievable brake squeal problem. My mechanic recently replaced the front pads and rotors. Prior to the replacement, there was no brake noise to speak of. Shortly thereafter, I began to have squeal problems. The squeal is only a problem under light brake pedal pressure, and at low speeds, just before coming to a complete stop. However, about 40% of the time, just before coming to a complete stop, it seems to me that the ABS system comes on, and I feel a shudder in the brake pedal, I hear that thumping sound, and the car almost lurches forward a little as the clamping pressure seems to release somewhat. This occurs even though my pedal pressure does not vary.
The mechanic has already tried putting factory pads on, but if anything, the problem is getting worse every day. I made sure that he used the blue Mercedes paste on the back of the pads. Other than the pads and rotors, what else could be causing this problem? I am most distressed about the strange ABS behavior at extremely low speeds. Thankfully, when braking in any other circumstances, the brakes perform flawlessly. However, driving home in bumper to bumper traffic is literally unbearable due to the noise.
I am due back to the mechanic in a couple of days, and would love to have some suggestions before then. Thanks a lot in advance!