2012 MERCEDES-BENZ C300 Suspension Problems

Mercedes of Danbury replaced the rear sub frame CODE 3441 47, since my mechanic (Newtown Auto Repair) told me that the Front subframe is in real bad shape, rotten/rusted, that it is dangerous to drive the car in this condition since the wheel and steering components are part and attached to it, the car would be out of control and all over the road any of these components fail and pull / brake away from the rusted out Sub Frame. When I brought the car in was under the impression that Mercedes Benz would replace front and back Sub Frames. But now they informed me of only recall on rear subframe, rear subframe will let go wheels will collapse, front controls the car and failing could kill people and total the car. frames.

Rear subframe crossmember rotting, needs replacement. It seems to be a common problem with this vehicle and the assumption by most professional is that it a faulty part supplied by a third party to Mercedes. The rest of the cars undercarriage is pristine, making me wonder why just this one part would rust out.

Took the car in for an oil change and asked them to look at the brakes and rear as there was a strange noise. Vehicle was inspected and found the entire subframe is rotted. Was advised this is a common problem with Mercedes and there were some recalls. Unfortunately no open recall on this vehicle and it is now not driveable as this is a safety risk. Car has been driven 60 miles/day for the past 3 months and could have had serious consequences.

The contact owns a 2012 Mercedes Benz C300. The contact stated that while driving at various speeds, the vehicle would shake without warning. The vehicle was taken to an independent mechanic for a tire rotation; while there, the mechanic discovered severe corrosion on the vehicle's subframe and the contact was advised to no longer drive the vehicle. The manufacturer was notified of the failure. The vehicle had yet to be repaired. The failure mileage was approximately 160,000. The VIN was not available.

The subframe has developed extensive rust and corrosion, which I believe is a result of faulty manufacturing. This corrosion has severely compromised the structural integrity of the subframe, posing a serious safety risk. The corrosion appears to be inherent to the materials or design used in the manufacturing process, leading to the rapid deterioration of the subframe. There are also no warning lights or failure indicators for this issue. As a result, the subframe is at risk of collapsing, which could cause catastrophic failure of the vehicle's suspension and steering systems. This situation creates an immediate danger to both the occupants of the vehicle and others on the road.

My 2012 c300 has a rotted rear subframe making the car not able to be driven. It has major ,life threatening, costly damage and this issue already has a recall all over the world but not in the United States. If I can get the assistance to pay this repair, it will be gladly appreciated.

Took my car for a doorknob repair and was told the whole subframe is rotted. They told me not to drive the car on the highway. The car brakes very hard to the right and always goes right while making cranking noises. Car feels very unsafe. I paid a lot of money for this and own a 2012 c300 4matic.

Subframe rusted and broke. It is available for inspection. Burlington Mercedes inspected the vehicle and told me it was not safe to drive. Mercedes-Benz USA is aware of the problem. They issued a letter extending the warranty covering only the subframe to twenty years and unlimited miles. Burlington Mercedes refused to do the subframe replacement without installing all new arms, which are currently not damaged. The cost to install all new arms is $2826.54. Mercedes-Benz USA is offering a warranty extension that their dealerships refuse to honor. This needs to be turned into a recall instead of a warranty extension. This subframe issue is dangerous. It affects Mercedes vehicles dating back to 2005 and encompasses many of their models including: SLK- Class, CLS-Class, SL-Class C-Class Sedan/Coupe, GLK-Class E-Class Sedan/Wagon, E-Class Coupe/Cabrio

The contact owns a 2012 Mercedes-Benz C300. The contact stated while driving at an undisclosed speed, he heard an abnormal sound coming from the rear of the vehicle, prompting him to pull to the shoulder of the roadway. After a visual inspection, the contact observed that both trailing arms had become detached. No warning lights were illuminated. The vehicle was taken to an independent mechanic, who determined that extensive frame corrosion had caused both trailing arms to detach. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 143,000.

While I was driving my 2012 MB C300 4Matic Sport Sedan in Nov', 2023 with history of regular maintenance, noticed a pretty load knocking noise, shudder and drifting to left a bit when it brakes from the driver's rear side especially on the highways. I took it to our local mechanic who was horrified to report that the sub frame was broken and completely rotten out too specifically rust issue with the rear suspension-rear subframe. He gets other German Cars like BMW & Audi even older and more miles in Chicago but none have rusted so much as these MB C-Class cars. Knowing the Dealers wont accept it a manufacturing defect, he was planning to repair it (no chance of wielding that thin metal sheet as the likelihood of breaking it is high). I was surprised to see 2010 Chevy Impala having a much more robust under the cover protection...

vehicle sub-frame is cracked rusted corroded.

the rear subframe broke while in motion and caused the car to drift and bounce while i was cornering the traction control and stability control intervened and i also counter steered once back in straight line i braked and the car tilted on the side, we lifted the car in a mechanic shop and found a rotten subframe one side broke the other was almost giving up.

a rusted rear subframe is more prone to crack when a driver hits a pothole or wants to brake quickly, which can lead to instability in the vehicle's rear suspension.

My rear subframe has corroded and has snapped, which is a major safety issue as while driving when I come to a stop the rear end of the car swags sideways. It do not stop straight.

Rear driver side wheel was making a clicking noise leading us to believe there was an issue with the strut and/or shock. Due to the nature and severity of the noise, we took the vehicle to our mechanic ASAP. Upon inspection, mechanic identified that the sub-frame had completely rusted through which could lead to other catastrophic issues making vehicle no longer safe to drive unless repaired. Due to the age of the vehicle being 11 years old, the cost to repair was almost the value of the vehicle basically making this a complete loss. I understand that Mercedes Benz has extended the warranty to 20 years for this issue for other models identifying that it is a design/parts defect but not the C300 although I have found that this is also an issue for this model.

Failure of rear subframe causes car to lose control. Only found out about the problem after I received a Mercedes extended Warranty in mail March 2023, roughly 6 months after OEM Undercarriage failed and forced me to purchase another Undercarriage in cash/no insurance involved because part back ordered for many months. Car thus inoperable for roughly 4 months. At moment of the OEM failure, total loss of control. Mercedes refuses to reimburse for cost of replacing undercarriage regardless of the fact that failure occurred before notification and regardless of fact that part unavailable for months

I found out about the Mercedes Subframe failure issue after having problems on the road, that could have killed me, and being warned not to drive anymore by an authorized repair shop because my vehicle was not safe for me to drive. This has caused many other issues with my cars mechanics due to this defect from the Mercedes factory.

The rear subframe rusted prematurely and broke off important mounts for the suspension and steering. I was driving and had to hard brake. This cause the back end of the car to swerve and almost lose control. I then heard a knocking sound when I pressed the brakes, prompting me to take it into the shop. There I was informed the the subframe was rusted and the vehicle wasn’t safe to drive. I filed a claim with my insurance, but they said it’s wear and tear.

I was driving on the freeway and had to hard brake due to unexpected stopped traffic. When I braked the vehicle veered hard to the left and almost lost complete control of the car and nearly caused a serious accident. I drove immediately to a local MB dealer and they confirmed what I was afraid and suspected which was the right rear subframe needs replaced. This car was recently sold to me by a dealer less than a month ago and not a single warning light or indicator warning me of this issue. The repair is over 7500 and the shop highly recommended I no longer drive until it’s replaced. This problem is very common and MB actually covers the cost in Europe and Canada.

The left rear weld of the subframe on my 2012 C300 4matic has rotted through and appears to be a manufacture's part defect. I found out about this issue from a brake inspection and told it is a safety concern, which Mercedes Benzes is aware of but has no recalls for the defect.

A problem with the rear subframe had occurred in which it had started to rust. Due to the severity of the issue I noticed my car started veering when hitting the brakes as well multiple concerning sounds and stability issues with the vehicle. Mercedes has not contacted me about replacing the part nor has their been any warning lights or any indication of the issue being present other than when the subframe had already been rotted. When speaking to MB about the issue their was nothing they could do for me which is questionable being that the cause of this is a manufacturing issue. I have yet to receive any information as to how the issue may be resolved. Not only does this put myself at my family at risk but as well as the community around me. Wether when braking my vehicle may veer and cause a collision or...

The subframe assembly on my car is defective, as I learned today from my mechanic. This issue is known for my model of car and widely reported online. The mechanic says they have seen this issue before. I heard a strange noise while driving so I took the car to the shop after 60 days of enduring the sound. The shop immediately deemed the car unfit for driving and unsafe. In their words, if I had hit one bad pothole, the wheels could have come off the back of my car, and my gas tank could have been punctured, leading to a potentially catastrophic accident. I am lucky to have gotten this defective part identified before being injured, and others need to be protected from this outcome before a serious injury occurs. As of now this has only been inspected by the shop doing the fix. People online have indicated...

My vehicle had started swerving when I had hit the brake. I noticed that my rear subframe had been rotting and did more research only to find that this was a common problem amongst Mercedes Benz owners. This is a huge safety issue as not only does it put my cars entire suspension at risk and cause a life threatening accident to me or others on the road it is also very concerning when my vehicle creaks and makes constant noises when driving. There are times it feels as if my vehicle’s suspension will fall out from under it and has been a clear issue Mercedes is aware of yet I have not received any recall notice nor have I gotten any answer as to how Mercedes can help me fix an issue they continuously overlook and sweep under the rug. I fear that eventually something will happen and have...

The left side of rear subframe has rusted out. The right side had been repaired by welding by a previous owner. The damage is still present and can be inspected. The broken bracket is right next to the gas tank and can possibly contact or dent the tank during a hard break or collision. This is a common problem with many people expressing this online and at the 3rd party repair shops. No warning signs were present until the bracket snapped. Extensive rust and corrosion around the area, specifically on the inside of the subframe.

Issue with my rear sub frame rotting out due to rust almost causing a very bad accident in a hard braking situation

Cradle and subframe are completely rusted out. This a widely common issue with these cars and am reading it across several forums. Other c300 owners say they have had the exact same issue and request for the MB dealership to fix it. Instead they are given a quote of nearly $10,000 to fix it. MB is responsible for this.

During planned car service my mechanics discovered that rear subframe is broken and is not safe to drive anymore. After investigation I found that this is a major issue that Mercedes owners have with this particular model. In Europe for this issue has been issued Recall, however in US for some reason Mercedes don't take responsibility. This is a major Safety hazard with possible fatal consequences.

Sub Frame broke from rust. Mercedes Benz has acknowledged the issue in Europe and repaired/replaced the part at no charge. Numerous problems and complaints can be found on line indicating that we, the car owner must and can complain to Mercedes for partial or complete support on the repair. But they do not acknowledge the problem in the US.

I was driving our Mercedes Benz C300 and noticed the braking distance taking longer than normal. Also, the rear end responding differently than normal. We took our Mercedes C300 to Mercedes Benz Dealer to be serviced. The technician looked under the car and found the rear subframe rotted out. The service advisor informed us of this being a known defect. We have to be cautious about driving the car until it's repaired due to the fact of being a serious safety issue. MB needs to recall these vehicles and repair them before someone is seriously injured in an accident. Many drivers are uware their subframe has rotted out. I've taken this car to the same MB shop for 8 years and all in a sudden this comes out of nowhere.

Rear Sub Frame Assembly failure. It is available for inspection upon request. Vehicle rear end begins to wobble at speeds above 40 mph. The issue causes steering to become more complicated and the vehicle veers sharply while braking. This issue makes all C Class vehicles with this Sub Frame Assembly extremely unsafe, especially at highway speeds. Vehicle has been inspected by the authorized Mercedes Benz dealership in Indianapolis, IN. Service Advisor stated it's "amazing" that there hasn't been a recall issued yet. Based on this body style there have been roughly 320,000 of these C-Class vehicles sold. If the NHTSA truly cares about safety, they will launch an investigation into this matter. There are no warning lamps or messages that appear prior to this failure.

Corroded rear cradle driver side. Causing instability driving. Cradle on back order for months according to local Mercedes parts department

Applied brakes coming down a slight grade and vehicle made a clunking noise and became unstable. Pulled and pitched as brakes were applied and released. Upon checking brakes it was very visible that the rear subframe had failed on the right side and the left was severely compromised. I hard braking situation would have resulted in a crash… The severe damage was not visible a week ago until it rotted out from the inside and failed under load.

This issue concerns rear Sub Frame corrosion. My car has always been serviced at the Mercedes Benz dealer where it was purchased as recommended. Upon recievieing my car after a service I was informed that the subframe in my car was badly damaged by metal corrosion. In fact I was told that the car was unsafe and should not be driven as total failure would likely cause lose of control of the vehicle. I was offered a repair quote in excess of $5,000 to replace the rotten subframe. I have since found that this failure is common the the model and many cases have been reported. In Europe and Canada recalls have been issued. Cases in the US are apparently felt with on a "case by case" basis. I see this as a serious safety concern for our highways. Failure is common from reports and and serious accidents surely possible....

The contact owns a 2012 Mercedes-Benz C300. The contact stated that upon taking his vehicle to a dealer for maintenance repairs; he was provided an estimate for the repair of corrosion to the rear subframe of the vehicle. Upon investigation, the contact discovered that the failure could lead to a potential braking system failure. The manufacturer was notified of the failure and informed him that there were no recalls on the vehicle. The vehicle was not repaired. The failure mileage was approximately 97,000.

I went to my dealership for a routine yearly service appointment, which I do regularly, along with yearly inspections. My car was purchased new to my liking in 2012 with input from my late partner who passed before I received it! I waited quite some time to get my gem. When it arrived, I had all I could do to drive it, given my loss. I garage it every day for the last 10+ years, never left it outside, it is pristine, only has 64,000 miles on it. To my disbelief, was informed by the MB technician yesterday that I have corrosion on my left rear sub panel, and that I should not drive it and consider a trade-in - NO WAY!! And that the part would cost me over $4,800 to replace and it would not be available until February 2023. So, I should drive another car, which I...

The contact owns a 2012 Mercedes-Benz C300. The contact stated that upon parking the vehicle at the dealer parking lot, she heard abnormal sounds coming from the rear of the vehicle. There was no warning light illuminated. The dealer diagnosed that the rear subframe was severely corroded and the rear control arm was detaching from the subframe. The dealer diagnosed that the subframe needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline. The failure mileage was approximately 79,000. The contact was informed by the service advisor that the vehicle should not be driven until it is repaired due to the extensive damage to the subframe.

Rear Subframe Cracking in Mercedes Benz 2012, C- Class, Sports. It can be life threatening for driver and passengers. Cost is $5700 for repairs. This replacement is free in Europe and Canada.

Rare Subframe breaking off parts are not available for at least 6 months. I have kids and mechanics advise me to keep it off the road. My only means of transportation

the back sub frame rotted away from rust

The contact owns a 2012 Mercedes-Benz C300. The contact stated that while having an oil change performed on the vehicle by an independent mechanic, he was informed that the cross member was severely corroded. The contact was informed by the mechanic that the vehicle was unsafe to drive. Neither the dealer nor the manufacturer had been notified of the failure. The vehicle was not repaired. The failure mileage was approximately 125,000.

Diagnosed with broken rear sub frame: "Broken rear sub frame, left side lower link is broken off and contacting Fuel Tank. Rear tires are also bald and care is unsafe to drive". Recall in Canada, but not USA. Sub frames on backorder until January 2023. I have three years of payment left, and am now being quoted 6,300 from the MB Service Ctr in Wilmington DE to fix this problem. Again, the items are on backorder due to heavy demand. Im a single mom we depend on my car to get us to work. This is the ultimate catch 22 as the car is extremely dangerous to drive and put us all in serious jeopardy - but no one will take this broken car as a trade in. I am forced to drive the vehicle while I wait for backordered parts and pray that I can get a loan to...

The contact owns a 2012 Mercedes-Benz C300. The contact stated while driving 25 MPH going downhill, the rear end of the vehicle shifted independently to the right. The contact stated no warning light was illuminated. The contact was able to continue driving at a slow speed to her destination. The contact stated her husband inspected the vehicle and became aware that the rear subframe cross member had fractured due to corrosion. The vehicle was not diagnosed or repaired. A dealer was not contacted. The manufacturer had been informed of the failure. The failure mileage was approximately 149,000.

Subframe corroded/rusted out. Car is in excellent condition with no other rust or corrosion. Car has 58,800 miles and regularly maintained by dealer. Took car to TireDiscounter because of noise. Mechanic put car on lift and reviewed corrosion and other damaged cause by failed part. Mechanic called MB service department and was told that parts on 5- 6 months back order because of this issue. But no recall even though problem is wide spread. Rear tires and gas tanked damaged by loose subframe.

I ran off the road and my rear suspension sub frame literally broke in half. Upon further research I’ve learned that these parts are faulty and several people have had theirs rust completely in two. Mine had lots of rust damage and that is likely what caused the damage to mine when I ran off the road (MINOR impact that should have never caused that much damage). Mercedes has recalled this part in several countries including Germany and Canada. When I drove home after running off the road my car was nearly impossible to drive. It was jerking all over the road and when I tapped the brakes the rear end of the car would come up off of the road (into the air)! This was in June. It’s now September and I still have not been able to obtain a part from Mercedes. So many people are having this...

Dealer states that the rear subframe has rusted and degraded to the point of requiring full replacement. The car is 10 years old with 98,000 miles on the odometer. This is premature degradation of an essential component.

2012 Mercedes Benz C300 4-Matic; Failure of rear subframe, significant crack of an important support member; very limited minor corrosion of the other parts of the frame, seems to be a manufacturing quality defect in a very specific part. Vehicle has been inspected by a highly qualified independent mechanic and by the closest manufacture's dealer in Massachusetts. Car cannot be driven because it is unsafe to do so. Both the dealer's service department and the independent repair shop have advised and confirmed this. Limited research online seems to indicate that this problem is well known by Mercedes Benz, and the manufacturer has issued recalls in other countries and has taken some responsibility for this defect. However, in the USA, Mercedes Benz has not issued a recall, to the best of my knowledge. It certainly seems that they should have done so. It is highly likely that many owners with this...

So here I am - another "happy" driver with a rotten subframe. Started noticing instability on the highway speeds a few months ago. Cracking noises lately. Since I use this car my very honest mechanic immediately told me that my rear subframe is completely done and I should not be driving the car until it is replaced. He quoted me $4500 (OEM parts + labor), but suggested that I take my car to MB and insist on covering the repair costs as this issue did not seem typical to him at all. I started googling and ended up here. Seems like this is a common issue and sounds like MB will replace the subframe for free in some other countries (cananda and Germany, .The dealer said the repair will cost Over $5000.00 This is a safety issue, A real big one. And the fact it's covered in other countries is...

The rear sub frame has rusted out and broken causing the car to veer suddenly to the left during braking. A quick search of the internet reveals that this is a common problem with this car. The dealership has quoted me $4,000 for the repairs.

I was traveling at roughly 55mph when I had to make a sudden deceleration due to another vehicle pulling out in front of me. When I applied the brakes, the car unexpectedly pulled violently to the left nearly causing a head-on collision with an on coming vehicle. After Googling the symptoms/scenario, I found that this can be caused by a rusted and failed rear suspension subframe. The control arms for the rear wheels become detached from the subframe as a result. Based on my research, this seems to be an extremely common occurrence. So much so that Mercedes Canada and Mercedes Germany are replacing the defective subframes free of charge as they’ve concluded the cause to be “inadequate corrosion protection” applied to the inside of the subframe. It seems as though they’re rotting from the inside out. After learning everything about the issue, I pulled my car on to ramps...

Part number: 207-350-97-02 This is the sub frame part number, during routine maintenance i found a cracked rear sub frame mount. Upon googling, there are hundreds of owners with that same problem. Cars with milage ranging from 40,000-150,0000 with the same issue. Under hard braking the car is unstable. When I called the MB dealer to inquire about the problem they did confirm that the problem is known but is not a safety recall and the repair bill is near $5,000. So Mercedes, confirmed it’s a known issue with a faulty part, confirmed it was a safety issue with the 2008-2012 Mercedes c300 and is not covering it.