2012 Mercedes-Benz C-Class Suspension

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 in my garage and was able to confirm that my subframe had indeed failed. This is a serious safety issue which is being addressed elsewhere. During my research I was unable to find a recall or TSB related to this issue, only hundreds of people stating that Mercedes forcing customers to cover the cost to repair this extremely dangerous manufacturing defect.

the back sub frame rotted away from rust

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.

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.

The rear K frame on Mercedes Benz C300 totaly rusted through and broke apart causing the entire rear of vehicle to rest upon the fuel tank. The failure also caused stress on rear brake lines. The vehicle is 10 years old with 90,000 miles purchased brand new and garaged. Mercedes has performed a recall on Canada vehicles but no USA vehicles. This is total negligence. This is going to cause a fatality. Either a vehicle will catch fire or brake lines will fail and cause an accident. The vehicle is known by the dealers to have this damage/failure. I googled and found numerous cases. Mercedes was not willing to stand by the vehicle and repair. This should be a recall like it is in Canada. I was quoted $5000.00 to repair by Mercedes.

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. I have removed my car from service, but many are being driven right now. Mercedes Benz is aware of this and is doing nothing to date to take responsibility for this design/construction defect. I add my voice to the many that I hope have contacted you with concern.

I took my vehicle in for a state inspection and was informed the rear subframe was rusted/rotting and on the verge of detaching. Had this happened while driving, the results could have been catastrophic. The vehicle cannot be driven until this $4K dollar repair is completed. Upon speaking with the mechanic, this is a well known issue within Mercedes. Had I not asked for an alignment, this would have remained undiscovered until it inevitably broke off while driving the vehicle. This is a major safety issue and a safety recall should be issued.

Rear subframe failure caused me to loose control of vehicle almost resulting in a serious highway accident. Rear driver side stabilizer subframe mount was completely corroded and broken away from the subframe. There is no other significant corrosion on the subframe. MB claim normal corrosion however the pictures tell a different story.

While performing service inspection, technician found REAR SUB FRAME RUSTED AND READY TO BREAK. Told they needed to show me the problem on the lift, as it was a serious SAFETY ISSUE and should be IMMEDIATELY REPLACED. Dealer and service acknowledged that this is a KNOWN and WIDESPREAD PROBLEM in C Class vehicles. Cost to replace quoted at $4200. No warning - thankfully inspection found before I was in a serious accident! Mercedes should issue recall for failed/corroded frame. Not the "safe" vehicle that Mercedes claims. (Car has been dealer serviced regularly, garaged, and 34,000 miles.) Owners shouldn't have to suddenly come up with $4,200 in order to drive their seemingly normal car. DANGEROUS.

The rear subframe rusted through causing mounting point of the torque link to fail. As a result, the car looses control when braking going sideways. Luckily, I discovered it when testing brakes after pad replacement in a safe setting. To my understanding, there are many other W204/W212 cars affected in the US with that issue. Mercedes so far does not want to take responsibility and recall cars for this issue which is a huge concern.

The contact owns a 2012 Mercedes-Benz C300. The contact stated while driving approximately 15-20 MPH, there was a rattling noise heard and the vehicle was pulling to the right. The vehicle was taken to the dealer and diagnosed that the rear subframe was rusted and had fractured. The vehicle was not repaired and remained at the dealer. The manufacturer was made aware of the failure and opened a case. The contact was awaiting a call back from the case manager. The failure mileage was approximately 120,000.

The contact owns a 2012 Mercedes-Benz C300. The contact stated that while driving at various speeds, the vehicle would drift from the center in either direction without warning. After describing the symptoms to an independent mechanic, he was informed that the rear subframe might be corroded. Upon inspection, the contact discovered that the subframe had started to corrode which had caused the failure. The dealer was notified of the failure and informed him that they are aware of the failure however, there was no recall regarding the issue. The contact attempted to notify the manufacturer of the failure but was unsuccessful. The vehicle was not repaired. The failure mileage was approximately 80,000.

DRIVING LOW SPEED IN TOWN IN FAIR WEATHER AND HIT BRAKES, NOISE AND STRANGE "LOOSENESS" IN BACK END. HAD NEARBY SERVICE STATION INSPECT AND REAR SUB FRAME HAD RUSTED OUT, SEARCHED AND FOUND MULTIPLE REPORTS OF EXACT ISSUE. CONFIRMED W/ LOCAL MB DEALER KNOWN ISSUE AND THEY ARE SEEING ABOUT 1 MONTH NOW.

THE AIR SUSPENSION IS FAULTY AND LEAKS. I HAVE HAD THE SINCE 2013 AND THE SUSPENSION HAS BEEN REPLACED ON ALL FOR WHEELS WITHIN DAYS OF EACH OTHER. COSTING THOUSANDS OF DOLLARS IN PARTS AND LABOR.