Hello:

I got Brake Pad Lining Wear error which I believe indicates the car needs new brake pads. For those of you who replaced the pads themselves when getting this error message, did you compare the old pads with the new one and see if the pads is really wearing out?

I took a look at my pad and it looks like it is still having a good amount of thickness, probably around 50%. Any idea at what percentage will the brake pad sensor triggers the warning? Seems like Mercedes is very conservative and designed the sensor so that it gives warning when the pad is at 50% thickness.


Thanks

Did you check all of the pads? Different models and years varied on the number of wheels that had sensors. The sensors are placed in holes in the pads so when the pad wears down to the sensor it wears the sensor and trips the light. No way it would trip at 50% wear. The rule of thumb per MB is you have 1000 miles left after the sensor opens but I think it's actually more. It's also possible the sensor wire could be broken and give you a false signal.

The sensor can also fail causing the error at any time.

Yep likely a sensor wire. I've driven 2200 miles with the wear lining message.. no issues. I wouldn't go past that, though.

Agree with the others, you may have a faulty sensor. I keep a regular eye on my pad wear. I am at almost 99K miles on the factory pads, and should have my front sensor trip anytime now. Once it does there is ~10% pad left. Nothing conservative about that. The sensor is placed in a perfect position IMO.

To achieve 100,000 miles on original pads is a good effort. I assume your rotors are original too.

I will be lucky to get 60,000 miles ( 100,000 km ) out of my rotors. My pads are wearing well.

Is the MB sensor just a wired in lead' bead' in the brake pad material which alarms when it goes to earth against the rotor ? . This is how my previous cars have operated.

Yes rotors are original too. Though last time I checked the rotor thickness they were close to the minimum. So, they may very well be below minimum now. I drive 80-90% highway, and tend to use the manual mode of the 7G when in traffic, so that is how I got the life out of them.

The sensor is just a normally closed contact. Once the sensor contacts the rotor, it begins to wear away at the contact of the sensor. Once it wears enough, the sensor contact is open, and once an open is sensed, you get the brake wear indicator. So, if something breaks the wire on either side of the contact, it will trip a false brake wear indicator, which I believe may be the OP's issue.

Good info , I suppose the downside of the old system is that it can become disconnected & it does not let you know !!



Thanks John.

JC - The sensor is a separate unit that fits in a slot in the pad. It's not embedded in the pad like others have been. What is inconsistent is the number of sensors per car. My SA built C240 had one on each wheel. Some cars on this forum have only one on LHS front. I have not checked my CLK yet. The CLK has larger brakes than the C but all signs are that the lady that was first owner of my car was a gentle driver going by tyre wear etc., but my front rotors show quite a lot of wear while the pads are healthy. I've already run on quite a few Km's enjoying the car.

Thanks Glyn, I think mine has all wheel sensored.

Interesting about your rotor wear Vs pad wear. I can't say I am particularly impressed with MB thinking about this but there is no question about how good the brake feel is.

I am interested to know what your experts in SA know about this phenomenom.

Great to hear that you are enjoying the new one. If I am asked at the 'Pearly Gates' whose car I wish to come back as, I will ask to be Glyns!