When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi I started to get a check brake lining warning a couple of months ago. I don't drive much so there hasn't been a whole lot of trips in the meantime. As you might expect it has become more frequent with time. So I checked my front and rear brakes and while both were worn neither one was worn down to the sensor hole. I pulled the sensor and noticed that some of the coating from the sensor is missing which allows some copper looking material to show through. As the fronts were slightly more worn than the rear I went ahead and replaced them as well as the sensor which I noticed also had some of the coating missing. My thinking was perhaps the pads have some conductivity such that once they get sufficiently worn they close the warning circuit. Well as you might expect the warning message is still appearing. So either my hypothesis is incorrect and I have another issue or I also to change out the rear pads.
So the question is does anybody know if the check braking lining warning will come on prior to the pads wearing down to the sensor?
Hi I started to get a check brake lining warning a couple of months ago. I don't drive much so there hasn't been a whole lot of trips in the meantime.
As you might expect it has become more frequent with time. So I checked my front and rear brakes and while both were worn neither one was worn down to the sensor hole. I pulled the sensor and noticed that some of the coating from the sensor is missing which allows some copper looking material to show through. As the fronts were slightly more worn than the rear I went ahead and replaced them as well as the sensor which I noticed also had some of the coating missing. My thinking was perhaps the pads have some conductivity such that once they get sufficiently worn they close the warning circuit. Well as you might expect the warning message is still appearing. So either my hypothesis is incorrect and I have another issue or I also to change out the rear pads.
So the question is does anybody know if the check braking lining warning will come on prior to the pads wearing down to the sensor?
How do you know this warning is indeed from one of the pad sensors?
> Take a look with your scanner at live data for F-SAM. You'll see status of brake pad sensors.
Brake dust has metal particles but not enough to yield false positives.
Perhaps it's not the pads but master fluid level, ABS sensor.... any code pops up?
Last edited by CaliBenzDriver; 03-31-2022 at 06:27 PM.
How do you know this warning is indeed from one of the pad sensors?
> Take a look with your scanner at live data for F-SAM. You'll see status of brake pad sensors.
Brake dust has metal particles but not enough to yield false positives.
Perhaps it's not the pads but master fluid level, ABS sensor.... any code pops up?
So my title is incorrect. The message is check brake pads.
Don't have a MB specific scanner. I checked the fluid level when I did the fronts. It is just below the max level.
The brakes work perfectly. They actually seem a little smoother after changing the front pads.
I am going to swap out the rear sensor to see if that does anything.
I had the same issue, check brake pads on my previous car. The mechanic confirmed brake pads are fine, I believe there is a sensor that connects the body to the chassis that if gone bad sends that incorrect message. Either way have a certified mechanic check for both the brake pads need replacement or it’s the sensor.
Winning posters were Calibenzdriver who said that the pad resistance would be too high to short to the rotor. I measured across the remaining thickness on the pad to the sensor hole and it was an open circuit. Vinsingh was also a winner with the failed sensor diagnosis. I swapped the rear sensor with the old front sensor and the warning light is gone.
Losing poster was me for not reaching out to the forum first and not measuring the pad resistance before replacing the front pads. I had about 0.086" of pad left beyond the sensor hole diameter. The price of overthinking the situation. Occam's razor prevails again.
Confession time. I did not remove and re-lubricate the guide pins when I replaced the front pads. The brakes are smoother than before and quiet. What I did do is move the pins back and forth inside the boots. Do I need to go back and pull the guide pins out and clean and lubricate them? It's been about ~ 6 years and 50k miles since the pads were replaced last.
We are glad you've cornered your sensor problem.
I would totally go back and take care of lubricating your pins with high temp silicone lube (specifically *NOT* "high temp synthetic brake grease").
If your have floating calipers, the pins must promote easy sliding under braking power. The last thing you don't want is petroleum grease to evaporate or turns into glue under extreme heat.
Well lubricated sliding pins provide minimal effort to best stopping power.
Favorite silicone lube
good popular silicone lube
These advanced silicone lubricants claim 3000F working temps... that should be long lived for 30 to 40K depending how you heat your brakes.
So it needs to contain ceramic? I did get the silicone Sil-glyde based lubricant. How much do you think you need? They only sell it in little packets locally.
So it needs to contain ceramic?
I did get the silicone Sil-glyde based lubricant.
How much do you think you need?
They only sell it in little packets locally.
Sil-glyde is a good popular pin-lube... having ceramic infused seems popular too - Lots of claims are made by many companies to have the best product
Anything "high-temp silicone", 3000°F... as long as it is NOT "high-temp synthetic brake grease"... misleading junk good only for 3 month!
As for Qty...:
> Spray the internal cavity and pins with brake cleaner so old stuff is gone.
> Apply about 1 packet per wheel/caliper.
> You don't want to stuff the hole so pins have no place to get in...
This pin lube job will give you the best brakes with s smooth and powerful pedal, just like new.
While in there flush the old DOT-4, specially out of the rear wheels.
Last edited by CaliBenzDriver; 04-09-2022 at 01:00 PM.
Sil-glyde is a good popular pin-lube... having ceramic infused seems popular too - Lots of claims are made by many companies to have the best product
Anything "high-temp silicone", 3000°F... as long as it is NOT "high-temp synthetic brake grease"... misleading junk good only for 3 month!
As for Qty...:
> clean the internal cavity with brake cleaner spray and pins so old sttuff is gone.
> Apply about 1 packet per wheel/caliper.
> You don't want to stuff the hole so pins have no place to get in.
This pin lube job will give you the best smooth and powerful brakes pedal, like new.
While in there flush the old DOT-4, specially out of the rear wheels.
Thanks. Had the brakes flushed within the last 18 months.
03-31-2022, 12:59 PM
