Squealing brakes
 

My wife had new rotors and pads installed on the '88 wagon @ Tire Kingdom. Before the install, the brakes were squealing so I figured the wear sensors were scratching the rotors. After the install the brakes still squeal. She went back to TK and they said it was 'normal' for a car of it's age & weight. This can't be true. Normally I would have done the work myself but my garage is currently full of boxes leaving me with no place to do any work. I'v had tires from TireRack installed @ Tire Kingdom before and have been very please with thier work, but this has turned me against them. Is there something I'm missing? How can new pads & rotors continue to squeal (and I do mean SQUEAL)?

M/B brake wear sensors are electrical, not "squealers". I'd bet money they installed a really hard cheapo pad and that is most of the squeak. Rotor quality plays a role too, but its rare for a new rotor of any brand to cause a squeak..

Eventually got rid of my brake squeal. W126
 

My W126 had bad squealing front and worse in rear. Put disk brake grease on back and side of all old pads. Old ones came with the used car. 90% improved. Still squealed some when backing up.
Eventually changed to Duralast brand (AZ). Did not change or machine rotors. Used brake grease as before. Squeal 100% gone.

A very liberal amount of anti-squeal paste/goo is very necessary on the back of the pads. Most shops skimp on this. Either that or a really cheapo pad/rotor combination as mentioned above.

Your first line of defense is Mercedes brake pad paste on the back of the pads. Stage II is backing plates with the brake pad paste on the back of the pad and the back of the backing plate. If none of that works get some new softer pads, like dealer or PBR Deluxe, and apply the paste.

Oh, but it is ...

... when the parts are "tire kingdom" parts and the installers are "tire kingdom" guys.

Best bet is OE Mercedes parts installed following Mercedes specifications.

oldirty88, if you don't want to pay for parts from your local MB dealer then it's best to use Textar brake pads, ATE rotors and anti-squeal paste on each brake pad backing plate.

Recommend having a MB-trained indie work on your MB automobile rather than a tech unfamiliar with MB automobiles.