They almost always seem to break when you change out the pads. I havent done this yet but I am thinking of just stripping the end of the wire, placing it on top of the brake pad where it should be mounted, then using epoxy glue to hold the bare wire end in "mid air" suspended in epoxy. The stock sensor is pretty much the same only it is a bare wire embedded in plastic. The sensor seems to work by shorting the cirquit when the rotor wears down the sensor to the point where the bare wire touches the metal and causes the brake light to light up in your dash. If works could save you $50 on two front brake wear sensors.
My 2 cents

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1996 E320
2000 C230 Kompressor
1988 190e 2.3 - 225K miles, owned for 7 years. I cannot say enough good things about this car. Very well built, even at 225 it ran like new.