parkwood

Very helpful discussion for a non mechanic like myself thanks everyone albeit sad our fellow mb owner is putting up with a major flaw....

I am neither an engineer nor a sport or motorcycle driver/rider so maybe asking a really silly question but does 4matic have any influence on the situation. My 205 is 4matic.

Also I had the shock of replacing rear pads recently whereas it had always been fronts first so I discovered about the ebd system resulting in heavier rear brake pad wear...is it possible the 4matic system evens braking more than on the rear wheel drive or does the 4matic system make it worse by favouring the rear over the front?

is the solution a change to the programme controlling the brakes or just better quality rotors (discs to me) and if the latter mb should offer all distronic owners the upgrade sooner rather than later. This is a stain on their reputation for me.

robert c

I have had to replace the rear pads on vehicles long before the fronts in a slight few vehicles since disc brakes became standard but I always attributed it to the braking proportioning valve assembly at the master brake cylinder. The newer vehicles have added circuits to assist in braking performance so I am not certain why yours wore quicker. One reason would be the loading of the vehicle as a newer loaded vehicle probably does force more braking to the rear. I am not knowledgeable of those systems so will read the systems on GMC trucks.

I don't believe that the full time four wheel drive systems have an effect on this rotor problem as from my reading the main ones with the problem are usually none AMG rotor equipped cars equipped with autonomous systems, but yes, could have an effect on the wearing of your rear pads before the fronts due to the necessary circuits on these vehicles. I don't think MB will change the programming of the auto braking system as it seems that the system is liked by those who have it but they have to come up with a solution to duct or cool the front rotors or redesign the rotor itself in my opinion.
Robert

Egonvdv

for the moment the problem has "stabilised" and is still not as bad as last time (am now at 4.000km after disc change)
(sometimes it seems worse than other times... but maybe that's just me going crazy...)
tomorrow going to Italy for the weekend, (500km in one go and 500 back) so curious to find out what that will do to the brakes.
have not yet called the dealer though, will try to do next week..

Egonvdv

well it seems that if I drive for 45 mns at max speeds of 110km (like it do to work every day) the car doesn't vibrate all that much.
only on longer trips does it get bad.

I was very noticeable this weekend when I drove the 500km to Italy (and 500km back) whole car was shaking when braking on the motorway
at speeds between 130 & 90 km, but this morning when going to work I hardly noticed anything....

robert c

great observation. I am now absolutly convinced my theory of the autonomous systems is helping create this condition on rotors that can't dissipate the heat( non AMG). I would assume you are driving the vehicle to work but on the Italy trip turned on that autonomous system.
I just read the conclusion of one of the recent Tesla accidents. It seems as though the car was following another one that changed lanes due to a stopped fire truck or emergency responder vehicle just ahead and the Tesla system didn't see the truck and drove into it. The lady lived through it fortunately. It is becomming very easy for me not to like these systems.
This weekend the local MB dealer had a "school" on learning the functions of your new car. I went and did learn allot including a bit of a tour of a new Maybach. Oh, I did ask about the rotor warping issues and they have nothing from MB yet so I was told and they admitted they don't have a problem yet as they sell very few if any autonomous cars except the Maybach of course as I sort of think it is built into the computer systems on those cars.
I guess you are at the doors of the dealer this morning?
Robert

Egonvdv

both to work and Italy I drove the car in the same way. - IE; I ALWAYS drive with adaptive cruise.

So they only thing I can think of (but I know nothing about cars really) is that the discs get hotter during a long drive and then warp more...?

but that would mean they "unwarp" once they cool off, since on shorter drives I notice the vibrations less...?

will call the dealer tomorrow to see what's what …

parkwood

Have spent some time trawling the net and there are people out there that say the discs cannot be warped by the heat generated by braking as it just does not get to the furnace temps the discs are cast in. What they do say is the heat causes issues with the brake pads and the material they are made of ending up with deposits being left on the disc (rotor) which is what causes the vibration especially if it arises from a hot pad being left on a disc whilst the caris not moving ie at a junction or at traffic lights. Also it seems this it not just a mercedes issue with examples in vw and Volvo forums with long discussions 're using the handbrake v footbrake at junctions putting autos in park pattern v original replacement pads etc. Interestingly 3 to 5k km seemed a typical time frame for issues.
another article discussed discs (rotors) being out of true either by poor fitting (tightening of hub or wheel unevenly) or damage to the hub carrying the disc by kerbing. This also discussed the problem of brake pad material creating a high spot as well.
as I have said before I am not technically trained in anyway ( I am an arts and humanities bod not science&#128521 but i found the idea that it is possibly an issue with the brake pad material attractive especially as the automonous systems may use them differently to a human driver......
am tak8ng my c on a trip to Bordeaux Thursday several 100 km on the peage will see if using distronic throws up any issues.
keep us updated!

parkwood

Well I have just suffered a disaster and will not be taking my now dead c class to Bordeaux! Our garage flooded and water got in the car. the flood line was about 10cm above the door sill......It looked dry but the carpet was wet. The engine bay was submerged to the bottom of the grille. Car came up with loads of error messages Inc do not put into gear and take to garage so mercedes mobilo arranged for it to be towed away which was a difficult operation due to the cars location and condition with brakes fixed on....the E is due 15th June but we have been told it maybe delayed but had not had any substantive news....just hoping we get a loaner!

Egonvdv

oh man, what a disaster! Hope all will be fixed soon and that you can still enjoy your holiday

parkwood

Thanks. No word on the extent of permanent damage yet but am glad the car is at the end of its lease albeit the new e seems to be late for delivery. The garage are not keeping me as informed as I would like.
have you spoken to your garage yet and do they have any proposals?
entertaining morning watching the depannage agent extract the very dead car at 90deg from the desired angle out of an old open barn onto the recovery truck.......clever guy.

robert c

Parkwood
I hate to hear of problems like yours that you are powerless to do much of anything. This weekend about 120 miles from me up in Ellicott City Maryland there was serious flooding as the flood waters rushed through the town and the photos of cars stacked on each other was not good.
Your braking post was interesting as I have experienced the incorrect attachment of wheels causing the brake disc to warp. I also thought about the information you read about braking not bringing a disc or rotor up to the casting temperature. Interesting.
When "turning" or truing a disc or rotor on a lathe an extremely small amount of the disc is removed with each pass until the rotor is true then checked for minimun thickness. The amounts removed are dropped to a small bin for proper disposal and I believe every disc I have run on a lathe I have never seen a build up of anything but metal material from the disc. I would expect material on a race car disc though due to severe use.
Years ago I was an observer at a project where the temper of a metal bracket was changed but the device was not brought up to the casting temperature when the metal was formed. I just don't know.
Best of luck to both you and Egondvd with your items and let us know.
Robert

Egonvdv

PIC is on holiday till Monday (4 june) so will call back then..

ua549

Each week I do a few maximum stops from speed to heat the pads and remove any detritus buildup from light braking.

Egonvdv

And this works..?

ua549

I've never had any vibration or pedal modulation issues.

Egonvdv

i'll give it a try then, seeing as there seems to be no other solution yet...

ot1

parkwood

Thanks for your empathy Robert it is appreciated.

Currently I have had no contact from my garage and am not happy with their service in that regard. MB breakdown and their agents were top class and really quick and efficient and made use of text messaging effectively. My insurers likewise. But the salesman and service rep have just not been in contact despite my emailing them nor mercedes finance.
It seems from my insurers on line claims file the car is repairable and my garage are instructed to proceed but the extent and time of repairs are as yet unknown to me.

I now have an opel astra 1.4 turbo on hire from hertz (opel were a general motors company but we're sold to Peugeot Citroen last year). It has a few of the driving systems on it Inc a speed limiter. But unlike the mercedes iteration it only stops you accelerating beyond the desired speed but will happily allow the car to gain excess speed going downhill and just gives a warning chime. It is a manual gear change (14 yrs in autos manual is a learning curve especially as I only drove UK the manuals!). I raise this just to mention our cars may use the brakes to control their progress far more than less premium cars manufacturers and as a result are generating the issues experienced. Sooo disappointing all the alleged testing has not caused a rethink or redesign....

parkwood

Wondering if there have been any developments?

Never got my trip but going to the vendee this week. My car was borderline repair but the garage were not keen. I saw it Monday and nothing had been done to it. Currently using a c class 220d provided by garage and paid for by Merc. It is brand new which is nice. E is now in production schedule and should be here early Sept. Looking forward to it.

Egonvdv

hi. sorry delay but I have still not called the dealer... 'I guess I dread the reply which for sure will be "we don't know")
for the moment the vibration is not as bad as last time and very inconsistent.
I'm using @ua549 trick (heavy braking a few times a week to clean discs) and this does seem to help.
but ok.. must call dealer Monday - no excuses.

parkwood

I feel guilty now!

The c class loaner I have is a 220d sportline with the amg exterior and interror. Bit firm on the suspension after airmatic but not too bad. No distronic.

But the front brakes look totally different to my old 250d C which did have distronic. They are drilled and have a strange shaped backing plate I assume to dissipate heat obviously what previous posters talked about but seems odd that a lower performance car is given such brakes. Amg trim is of course just cosmetic styling.

parkwood

Still waiting for my e ☹ but was wondering if your braking problem has sorted itself? If so I assume the recommendation is to brake heavily a couple of times say in a week thereby removing any build up of brake material which may have accumulated from the distronic light braking?

Egonvdv

have had much less problems since the last time they changed the brakes.
still some light vibrations every now & then. it comes & goes it seems.
I have to take my brother's car for service on Wednesday and will ask them if a definite fix has been found for it..

Egonvdv

no solution so far according the the european (xentry) database
last news was from april when mercedes said a tool was in development to messure "something" (no idea what exactly)

parkwood

Thanks for updating much appreciated.

Was hoping to have heard from my garage re my car but as yet nothing. I have to go by the garage Friday so shall call in to see if I can get an update. Soon be 7 months since I ordered it😤