Today the yellow disc pad light on the dash came on. I assume its time for brakes. Is this all four wheels, front only. What type of service should a Mercedes receive, metallic pads, etc... How does the sensor get reset? Thanks...

Take a look in the Do It Yourself section of this site and read the Brake Job article. You will see the brake pad sensors there. You may have sensors on the front and rear pads. Without knowing what car you have it's impossible to tell. The light comes on when a pad wears down to the sensor and the sensor is grounded to complete the electrical circuit.
Bottom line, you need new brake pads and sensors. You can visually look at them to see how far they are worn. They come in sets...front set and rear set. Use only Mercedes OE quality pads from companies like Pagid, Jurid, Textar. We sell them in PartsShop. Go to PartsShop FastLane and enter the year and model of your car to see what we have.

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Bill Wood - Webmaster
MercedesShop.com, LLC

Take Webmaster's word and read the brake service article in the DIY section. However, your brake system might be different than the ones in the article (95 and 98 E class). I just replaced the front brake pads for my 94' C280. Let me know if you have a similar model. Actually I found it's much easier to replace brake pads for the C class (Single piston, floating type). You don't need to reset anything. Once you replace the bad sensor, the light in the dash will go away. Do use Mercedes OE pads and apply brake pad paste on the back and side of the pads.

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Harry (94 C280)

To clarify, there is no "reset" to turning the indicator light off...simply replace the pads & sensors and, with the system no longer grounding, the warning light will not iluminate.

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Best regards, Michael
'92 500E
'88 300TE

Two things that my mech explained to me: 1- Use OEM or equivalent pads. Avoid metallic like the plague, they'll eat your rotors.
2- Don't machine your rotors, just take a grinder and remove the lip that forms around the OD of the rotor, as long as the rotor is still within spec.

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Darko Vusir
1994 C220

Good advice Darko. One of the excuses outside techs give to unwitting mercedes owners for cutting their rotors is the excessive lip that sometimes appears at the edge. I had my rear rotors cut and now i have to order a new pair because the braking sound is now unbearable. Thank god i didn't do the same to my front ones the other week.

yal 230E (W124)

Is this true for 2004 C230 Komp Sport Sedan? Just want to confirm.
Thanks

I like Textar Yellow Box pads and Balo rotors (learned from this site).

Sometimes the lip on the rotor can eat into the sensor, even though you may have some pad left. On many cars you can look and seee if your rotor 'lip' is big through the wheel. Another indicator of this is if the light is on with no brake pedal. If it is worn pad on good rotor, then you can turn the light on and off with your foot. If the light is different, it is lipping involved, and maybe more.

Curious what anyone thinks "machining the lip off" accomplishes.

Seems to me it "hides" the evidence that the rotor is worn.

oh wow woah! If you have a lip, your rotor is out of spec -- too thin -- and must be discarded. For one you have lost enough of the heat sink of the rotor to be dangerous and allow fade.

A rotor can have a lip and still be well within specs. You have to measure it to be sure. I also see no need to remove the lip and never have.

I have never removed the lip either. Has not been an issue. I would thing that the low cost of new rotors and the time involved in "grinding" the lip off and the stress of "being carefull not to grind the rotors into a useless piece of metal" would be a good voice of reason to just buy new rotors if you were worried about the lip and the function of something as important as brakes. The rotors on most MB cars are very reasonable in cost. Some are down right inexpensive. And, no, I am not talking about buying the cheapest ones you can find that do not meet OEM specs. They are inexpensive, cetrainly for something as easy to replace and as important as stopping the car.