2018 S450
I replaced first set of brakes and rotors at 29,000 miles. quite pricey
now my brake pad light is on with just 46,000 miles. dealer said inside pad with sensor may be lower than the recently inspected wear from inspection of 7mm and 8mm.
dealer said brakes wear fast on this car from weight. I am not a heavy brake user or drive too fast.
I have never replaced rotors twice on a car especially with under 50,000 miles.
I have owned many Mercedes and always saw them as reliable and quality built. not needing brakes and rotors so frequently.
The car is great otherwise.
What is wrong?
Does the Distronic driving feature cause excessive brake wear? I do use that feature frequently
I am considering going to a small shop and just replacing pads to save cost.
Thank you.

 

Weight is meaningless. Ignore anything spoken from the dealer while his/her lips are moving.

MB brakes wear fast. Soft (fast wearing) compound is generally quiet and smooth. And check the contact area of the rear pads - pretty paltry, it means not much pad material volume in ccs is there to begin with. Fast wearing compound + not much pad volume = frequent replacement.

Porsche on the other hand are known for brakes that squeal and groan but they stop sports cars from “elevated” speeds repeatedly. So it’s a tradeoff.

And MB assist systems such as all variants of cruise control and lane keep systems consume brakes.

Fast inner rear pad wearout is common on late model MBs.

 

If you use distronic to maintain speed, any time it needs to slow the car it uses the rear brakes.
If you use lane keeping feature, there are adjustments it uses that use the outside brakes.

Myself, I quit using distronic and lane keeping for these and other reasons. I am at 40K miles and less then ½ way through the pads.
I got 90K miles on my 2005 4Runner brake pads--something that most people only get 30K-35K.

It is how you drive it (and how you allow itself to drive).

 

i replaced mine at 30K pads/rotors. at 60K i replaced just pads and sensors. Measured rotors, where within spec. First time dealer did it, second time diy. Mine wore our quickly first time as i used distronic a lot.

 

That’s pretty soon. Mine were replaced at around 34K miles a few months ago (rotors and pads, both front and rear). That matches the same interval on my previous W222 too. They are super expensive when u replace all 8 parts on front and rear, and 16K miles makes no sense. It might be your driving style (city driving, or highway with 100% adaptive cruise control…)

 

thinking of my driving style and enjoying the distronic feature for safety.
But as the car braked itself and slowed, I would push the accelerator to speed up. Essentially driving with brakes on.
I never really thought of it that way. or realized how quickly you can wear pads down.

Do you think it's safe to just replace the pads and not the rotors? just seems like such a waste of material and money.
does the dealer add anything to the repair equation or do you think a competent small shop would be be ok?

 

You only need to replace the rotors when they are worn down below the minimum thickness or are warped from overheating. Some dealers like to promote always changing the rotors when the pads are replaced which is a money-making proposition for them. And an independent shop can do the job as good as a dealer.

 

The only piece of good advice the salesman told me when I bought my CPO S550 last year was to not use the "lane keep assist" feature. It eats brake pads and rotors super fast. The lane keep assist feature doesn't steer the car with the steerinbg wheel, it brakes on the osspsite side to force the car over. When you're drifiting left, it applies the right side brakes to center you in the lane, and vice versa. I literally never use that feature. The downside is that the car drifts more when just using distronic plus, kind of a waste because it behaves like there a drunk driver in control, but not worth the expense of changing pads and rotors more frequently.

 

That's true. There is also an option in the setting that i turned on which changes the response of this particular feature from being sensitive to standard, or standard to dynamic (something like that, I don't recall the exact terms). That has reduced the sensitivity of this feature quite a bit. First thing I did when I got my car.

 

I can remove the braking from Lane keeping
so you keep the feature

 

I keep the nannie on. I use distronic in heavy Los Angeles traffic all the time. I have 47,000 miles on the car and only replaced pads not too long ago. I purchased a state of the art car with all the goodies for a reason. If I have to replace brakes more often so be it. Once exception, do not use distronic when going down long down-hill roads. Disctronic slows down the car only using the brakes, not the engine combined with lower gears. So when driving down mountains, I simply never use distronic.

 

I was told recently I needed a front brake job (Pads & Rotors w/ Sensor). My question is why would I have to replace the front brake sensor? The front pads haven't worn out yet and I have no message in the dash.

One thing I have noticed is that the S560 uses up brakes and tires more than any vehicle I have ever owned. It's not a gas hog as much as it is a maintenance item consumer.

 

A) no need, it's just a wire that gets cut when wear reaches it
B) rather change them because they are only on one side so cost is $10

 

I can understand it uses the brakes but it also uses the steering. I can feel the wheel move and I do minor corrections if needed. Sort of a minor battles of the minds - computer vs me. No way it only uses brakes to correct steering especially when in mountains on some switchbacks. It has been a question of mine how it slows going down hills so good to learn it’s mostly by braking, pretty sure it’ll hold a lower gear too. I’ve gotten in the habit of not using it on downhills and now I know that was a good move.

Overall I use it a lot and enjoy it for piece of mind on long trips and when in heavy traffic. Easy to turn off and take over too. And the stock brakes do make a mess. First cross country trip and the wheels were black, easy clean up, and I like how it stops.

 

just replaced front and rear brake pads. 35% less cost than dealer. found a very good local shop.
lets see if I can get 30-40,000 miles with less distronic use.
thank you for all the great help.

 

I don't know how to do the double quote thing so I'll answer in one place. You have 2 separate systems. 1.Distronic Plus. 2. Lane Keep assist. Distronic plus activates through the steering system, it actually turns the steering wheel for you. Lane keep assist does not. Lane keep assist applies the brakes on one side of the car; that force results in the car "pulling" to the side that the brakes are applied, which is why you feel the steering wheel turn. Hope that helps. I use distronic plus, but primarily for following distances. The systems work in tandem to provide a "semi-automonous" driving experence, but they are actuated through different systems on the car. Great idea, but I'm not crazy about the brake pad wear that results from Lane keep assist.

This video eplains LKA:

 

Good explanation and the video is still confusing.

There are three systems to activate, not just two, Distronic, and two buttons on the dash:
1. Distronic which is the fancy cruise control system that maintains a set distance to a car in front (which is annoyingly big enough of a gap to let everyone cut in front of you, even some 18 wheelers), plus it reads signs and other wiz-bang stuff, applies brakes, speeds up, etc.; then
2. Steering Assist which keeps you between the lines (and I use this all the time, and it’s the automatic steering I mentioned, no braking, just steering); then
3. Lane Keep Assist / steering wheel shaker (which I don’t use). Yes, it’ll apply crazy braking and flash red on the dash if it thinks you’re about to do something to win a Darwin Award. And on open or curvy roads I drive all over so the shaking steering wheel is annoying.

From reading the manual and living with it I think this is how it works.

 

Your 1 & 2 are the same. That's why it is called "Distronic plus". The old distronic systyem on MB was the radar cruise control feature only, but they added the steering feature to distronic, which is why it is called "distronic plus". I had a 2001 S600 with distronic cruise control, but it didn't do anything with the cars steering, FYI. Old system was "distronic" and new system is "distrnic plus" because it controls following distance and follows the road and cars in front of you, through steering wheel activation. As far as disctronic plus, your lower dash panel button enables the system, and your stalk both activates the system and fine tues the distance, which is displayed on the digital display as you make changes to fine tune the following distance.

As for LKA; the lower panel button enables the system. You can fine tune it with steering wheel buttons in the assistance section, I think there are 2 levels (adaptive & Standard) I don't use it so I don't knwo how they differ. It takes some time to learn how to use all the features, and which ones you won't want to use. There are a bunch of videos like that from MB that explain all the driver assistance systems in detail.

 

Adaptive features slightly less intervention for lane departure and LKA by the vehicle under certain condition; standard is a more involved LKA for those who prefers more autopilot-like interventions under most conditions regardless.

Unlike Standard, the “reduced” nature of Adaptive is that it will NOT intervene if:
• you accelerate hard, e.g. kickdown.
• you brake hard.
• you steer actively, e.g. swerve to avoid an obstacle or change lanes quickly.
• you cut the corner on a sharp bend.

 

You can have Distronic (adaptive cruise) active without steering assist or lane keeping assist. That’s why I called it three systems.

 

FYI, if you want to think of distronic plus as 2 systems that's fine. But there is no "steering assist" without Distronic activated. The steering assist is part of the Distronic Plus system. One button to enable and one movement of the stalk to activate it. Obviously you can fine tune it. But if you want to call it 2 systems for the sake of clarity, that's fine too Happy driving!!