I neglected to mention that MB uses DOT4+ fluid if you are buying any. And MB says do not machine the discs. If they are beyond service limits, replace them. They are not very costly in the aftermarket.

It doesn't sound like you are going to do the work yourself. If you do, you must remove the old pad on the piston side of the caliper so as to press the piston back into the caliper with a bluntish plastic or wooden tool. And to do this without forcing fluid backwards through the ABS pump, a bad thing, you must open the caliper bleed valve a bit while pressing the piston in, thus releasing the fluid. It will spill but it's water soluble. You can then pull the other old pad easily. You must replace the sensors which cost less than six bucks each.

Don't get any fluid on the paint.

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Roger E.