I noticed that my 911 brakes were getting a bit soft, so on the way to the FLAPS, my Mercedes "Brake Lining Wear" light comes on. So I decided to do both cars. 911 brakes were surprising easy if not the easiest I have ever changed. The rotors were good, so it was just the pads. Mercedes is ABS and I really did not know what to expect, but they were a piece of cake as well. However, I forgot to buy any brake grease. So I was pleased as punch with myself for getting them done in about 45 minutes, but the SCCCCRRRREEEEEETTTTTCCCCCHHHHH that came from them is unlike any sound I have ever heard. Enter 16 year old daughter, besides not using her own gas, she thought she would be cool to roll in the Benz with her friends while I was in L.A. (she did have permission), so off she goes and is pulling into the parking lot of the opposing school that hers was playing. 50 -100 kids in the parking lot and here comes cool chick in the Benz, when the brakes were necessary. EVERYONE in the parking lot turned immediately to look at her, and she said one kid even covered his ears. I am still laughing. Just pulled them out and put grease on them tonight.

Bed the pads properly and it should go away.

http://www.pmbperformance.com/page/page/1492423.htm

Heh, heh, heh.... all she had to do was hop out, holler "Sorry guys.... racing brakes. Don't you just HATE it when they make that noise!"... then be-bop on her way.

You've left out some information that could be helpful. What pads, what rotors, what sensors? What year and model is the Merc? In general, your FLAPS is gonna carry parts made to a price standard, NOT a quality standard. I suspect you got no-name parts at what you thought was a good price. Mercedes and BMW (along with Volvo) are REALLY sensitive to pad/rotor quality and compatibility. If you didn't replace the rotors, you made a mistake. (They don't respond well to turning.) Did you grease the slides? VERY important? Did the pads come with the anti-squeal backing? They should have. Did you use that paste that dries out? If so, you'll need to get that off and use a proper product.

The Cap'n

Yeah, if she knew racing brakes squealed like little pigs she may have got away with that

However, I use brake goo on the back of my race brakes and have never had an issue with them squealing.