CLA250 Brake Pad Sensor
This is a discussion on CLA250 Brake Pad Sensor within the CLA General Discussion forums, part of the Mercedes-Benz CLA Forum category; Brake pad sensor just went off on my CLA. I'm planning on buying the front pads myself and will have it replaced at a local ...
Brake pad sensor just went off on my CLA. I'm planning on buying the front pads myself and will have it replaced at a local shop rather than the dealership. Do I need to purchase and replace the sensor as well? Is there only one sensor (front right)?
Last edited by gvalenciano; 08-04-2016 at 12:23 PM.
I believe the sensor is attached to the pad . Once the pad reaches where the sensor wire is mounted in the brake it will break loose and your sensor will get tripped. Should unplug the old sensor and once you get everything fitted the new sensor plugs in.
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Yep, it's built into the pads. Just install and connect up. The other question is, do you need to replace the rotors at the same time?
How many miles do you have on your CLA that you have to replace the front pads??
Your disc brakes evolved from an experimental method of braking pioneered by the racing teams of Europe in the early 20th century. The way that many drivers know that it's time to replace their pads is through an alert from their Mercedes-Benz CLA250 brake pad wear sensor. As your Mercedes-Benz CLA250 brake pads begin to lose their friction material, a small clip or metal pin on the pad contacts the sensor and grounds the circuit. At that point, it sends a signal to your on-board computer and a light illuminates on the dash.
sensor and shim (hadware)
If you do your front brakes, would you mind posting 2 things?
1) Do you have electronic sensors on both sides or on one side only?
2) Do you have shims for your front caliper backet? (I Mean the stainless inserts that
would snap into the grooves where the brake pads slide towards or away from the rotor)
Just did my front brakes and rotors, and would like to compare notes.
My car only had a sensor on one side, and no brake hardware at all
(ie stainless steel shims)
If the electronic sensor looks un-damaged, it can be reused. It unplugs from the wire
and detaches from the pad. Damaged means the pad was worn so thin that a good
part of the sensor has also worn away. The sensor is just a hunk of metal that closes a circuit.
by touching the rotor.
If a big chunk of it has worn away, then it will let the pad wear down too thin before
it will make contact, so it is unsafe. Look at how much pad you have left. The existing, worn sensor will
signal when your new pad wears down to the same thinness.
Last edited by coder; 11-23-2016 at 08:58 PM.
Brake pad sensor - should you replace or reuse?
The sensor will not necessarily break lose, unless you wait a long time after the warning lite went on.
The way it works, it closes the circuit as soon the sensor touches the rotor, and that activates the light.
From the moment this happens, the sensor starts to wear, getting thinner.
It wears at the same rate as the pad does, so you have some time before the sensor wear becomes
a problem (a few weeks to maybe a small number of months)
The criteria for how much wear is too much ( in my mind) is how much pad you have left.
This is because there is only one sensor (on one side) and you want an early warning, with some
safety margin, so that the other side could not wear down to nothing and start damaging the rotor
as the naked backing plate starts biting into it. If you have less that 2mm of the pad left
get a new sensor.
If you do the pad replacement soon enough, the wear on the sensor
will be insignificant and it can surely be reused.
The sensor snaps into a little pocket on the pad's metal
backing plate, you can pry it off with a flat blade screwdriver.
There is no downside to reusing the old sensor if it is not worn.
It is just a piece of metal with wire and a plug.
There is literally nothing to go wrong with it, other than the metal electrode wearing
Dealers usually replace the sensor as a matter or procedure, They typically also replace
the rotors when they work on the brakes. This is optimized for maximum upcharge.
You, OTOH can make a rational call, based on evidence.
mine comes with only front right sensor, i replaced 4 rotors after 36600 miles, sensor was fine, rotors cracked on mine, they seem to wear out really quick
Cracked?? Going for a new 100-0 record? 😝
Originally Posted by omarlekphet
Hope it was warranty work ...
Hahaah yeah something that way, no warranty here for these rotors, i am amazed to know that there is warranty in the US
Originally Posted by jmc