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 that Mercedes will not fix the problem free of charge - and in fact they charge a premium to other places to replace this faulty subframe. There were zero warning indicators of this dangerous issue - the car drove completely normally aside from an infrequent knocking sound that would occur every 5-10 minutes under normal city driving conditions.

- Seattle, WA, USA

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.

- Perrysburg, OH, USA

As per an inspection by my mechanic, the rear sub frame of the vehicle has cracked due to rust corrosion and subsequent metal failure. I first noticed the issue when there was a thumping sound over bumps and the car started to swerve when applying brakes on the highway, quite a scary situation as I thought the brakes were failing. The car has 78000 miles and has had all maintenance done. The is no other rust on or underneath the car. According to my research on Mercedes-Benz owner forums I discovered that it is a common issue and that, so far, Mercedes Benz has not issued a recall in the US. According to these forums Mercedes has issued recalls in other countries (although I have not confirmed this point). The estimated cost to replace the sub frame is $3000 including labor and there is an 8 to 10 week backlog for the part due to the number of failures occurring. In the meantime I cannot drive the vehicle as my mechanic has told me that the car is not safe to operate.

- Darien, CT, USA

The rear subframe rusted and completely cracked. The car started to shake violently while I was on the highway. Fortunately I was in the right hand land and was able to slow down. I was driving in the car with my mother. My understanding from the mechanic is that we were lucky not to be killed or hurt anyone else. The frame is completely cracked. I called the local dealership and they said this is an extremely common problem. So common they have multiple vehicles on the lot waiting for parts, and the waitlist is indefinite. There were absolutely no warnings on the car.

- Alexandria, VA, USA

I have a 20212 Mercedes C300 with 70,000 miles. I took it into the MB dealership for inspection and was told that the rear subframe was rusted through. The subframe's failure also caused the brake lines to rust to the point of needing to be replaced. The subframe repair will cost $5,900 and the brake line replacement will cost around $1,200. The dealer told me the car couldn't be driven safely, so I had to leave it there to be repaired. There were no interior warning alarms about the structure or the brakes. According to forums on Benzworld.org, this is a known problem on these specific cars and the component is replaced for free by MB in Europe.

- West Chester, PA, USA

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.

- Wilmington, DE, USA

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

- Ashburn , VA, USA

- Right Rear Subframe; Yes, available for inspection. - My mechanic told me that driving the car more than 2 miles or at a high rate of speed was very dangerous. He told me there that if the car braked quickly or was driven at a high rate of speed that there was a very good chance of an accident. There is a risk of the right control arm detaching from the frame; this could cause the car to be uncontrollable with the right rear wheel and control arm detaching from the vehicle. - Yes, the issue was confirmed by my mechanic, who works at an independent service center. - No. - There were no warning lamps or messages. I had begun to hear a loud clunking noise, usually when braking.

- Jenkintown, PA, USA

I-€™m filing a complaint due to a concern regarding the rear subframe of my vehicle becoming rotted/rusted out and falling apart at any time. This is due to a Mercedes Benz manufacturing issue where they tried cost cutting which turned out very poor quality materials for this very important assembly. I have researched online about this problem, and turns out, it is very common with this body style c300 ('08 - '14). There are hundreds, if not thousands, of individuals within the USA who are having this exact same issue with as little as 60,000 miles. Most are happening around the 90,000 mile mark however. They primarily mention in many online forums how scared they were when it happened and how lucky they are it didn-€™t cause a major accident-€¦yet. My car only has ~110,000 miles and is just about 10 years of age. This issue should never happen for a vehicle with such low miles and such a short life, especially from a prominent and distinguished automotive company. This is a Huge Safety Concern, and I am Scared that this subframe will fail without warning and at a high speed, which can likely cause me to be involved in a major accident where people are killed or seriously injured. It is astonishing how this subframe was not recalled by now and how Mercedes USA has not taken responsibility for this. This issue needs to be addressed and recalled Immediately before people are killed or seriously injured, and before more of these parts break. Please look into this very soon as this is a very serious matter.

- Seymour, CT, USA

the Rear Subrame CRACKED while Driving, Almost causing a Major accident with my son in the car as well. This seems to be a MAJOR problem being overlooked and ignored by Mercedes Benz. This repair is going to Cost me $ 3000-$ 5000 Dollars. and the Replacement Subframe is Impossible to find and on Back order ! so Now I'm without a Vehicle for God knows How long "? I Feel there is No Doubt this is a Defect and Should be Covered by Mercedes Benz and a Recall ! How is this not being investigated is Really Scary. How can a Frame or a Car just Crack " That's Not safe for ANYBODY !

- Sutton, MA, USA

During a routine oil change Mercedes mechanic discovered our rear subframe is rusted on both sides and needs to be replaced. This is apparently a well known problem, and Mercedes will replace this for free in Germany, but has not recalled the subframes in the US. Mercedes created a new OEM part as the replacement part, proving the original part is faulty. However Mercedes does not have enough parts ane every mechanic we have spoken with has several subframes on order for months at a time. We have waited 9 weeks at this point. Many Mercedes drivers subframes have broken making the cars undrivable.

- Falls Church, VA, USA

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.

- Milford, CT, USA

Took my car in for inspection at the Mercedes dealership. They advised the rear subframe was rotted or rusted. This occurred from the inside. The vehicle is garage kept. They advised Mercedes has no re-call on the issue in the United States. They are covering the issue outside the US. This is a major safety issue.

- Elizabethtown, PA, USA

Vehicle was in for state inspection at an authorized inspection station. It failed inspection due to severely rusted and deteriorated rear K-Frame which had to be replaced to pass inspection. This is a major defect I feel caused by manufacture negligence. There were no warnings, messages or any signals indicating a problem. This issue could have severely caused an injury or even death had it not been detected by the mechanic inspector. Mechanic stated to me that he had replaced several of the rear K-Frames in the last year on this make and model.

- Shippensburg, PA, USA

While driving recently we noticed that the vehicle pulled to one side while braking, and very hard under quick stop tests. Vehicle handling felt extremely dangerous when performing a hard brake test. An inspection was performed, and the service center found a rotted out rear subframe, and cracking around the suspension mounting brackets. After researching this repair, we found this to be a common problem in this and similar model Mercedes-Benz (MB) vehicles of that vintage. I understand that a recall may have been issued in Canada regarding this issue, but not in the U.S. Mercedes-Benz and their service stations have acknowledged this issue is common but they have not taken action to rectify this serious problem, or to compensate owners for the repair costs, which range from $3500 to $6000 depending on where the vehicle is serviced. We are the first owners of this car. It is barely 10 years old, is regularly maintained, and thoroughly washed during the winter months to remove road salt. A well maintained vehicle should not deteriorate this rapidly from rust, especially a Mercedes-Benz. We feel that it is unacceptable for MB to remain unaccountable for this problem.

- Elkhart , IN, USA

Per the dealership in connection with a regular service, the rear subframe rusted out and became structurally weak and was a safety hazard. The problem was confirmed and repaired by an independent repair shop. From Google searches, this issue does not appear to be an uncommon problem. Car is garaged and receives regular underbody washes for road salt.

- Old Saybrook, CT, USA

This is a followup to a previous report. I now have photos and the actual part that was replaced. While driving on secondary road at 45 mph, braked for stoplight in 2012 Mercedes C300 4matic. Car veered left, rear swung right, and right front dove downward. Luckily regained control and prevented swerving into oncoming traffic. Took car to my regular mechanic and it was determined that the welds on the left rear portion of the rear subframe had rusted out from the inside of the subframe, severing the attachment to the left rear wheel control arms. The car had been inspected 6 months earlier and there was no sign of problem. The failure was catastrophic, not gradual. Upon removal, it was also noted that the right mounting bracket was also in the process of rusting through and failing. When the mechanic called the local Mercedes dealer, the service manager was not surprised and proceeded to outline what parts would be needed to carry out the repair. When I contacted the local Mercedes dealer, myself, they said this wasn-€™t an uncommon problem, but there was not recall or service bulletin on the problem. Was given a rough quote of $5000 to affect the repair. I also contacted Mercedes Benz USA and was told there were no recalls or service bulletins, but they might be able to provide some -€œGoodwill Assistance-€ to offset the expected cost if I had it towed to a MB dealer and got a quote from them. Benzworld.org, an owners forum with over 5 million participants world-wide https://www.benzworld.org/threads/w204-rear-subframes-deterioration.3048088/#post-17965564 has multiple postings about the problem as do other forums including CarProblemZoo.com https://This design/manufacturer defect has had recalls in both Europe and Canada. Why this is not being addressed in the US? This sudden failure is potentially life-threatening.

- Bloomfield Hills, MI, USA

The contact's wife owns a 2012 Mercedes-Benz C300. The contact stated that upon taking the vehicle to the dealer to be serviced, he was informed that the subframe was severely corroded and could fracture. The manufacturer was notified of the failure and advised the contact that they could not assist as the vehicle was out of warranty. The vehicle was not repaired. The approximate failure mileage was 43,000.

- Cincinnati, OH, USA

While driving on secondary road at 45 mph, braked for stoplight in 2012 Mercedes C300 4matic. Car veered left, rear swung right, and right front dove downward. Luckily regained control and prevented swerving into oncoming traffic. Took car to my regular mechanic and it was determined that the welds on the left rear portion of the rear subframe had rusted out from the inside of the subframe, severing the attachment to the left rear wheel control arms. The car had been inspected 6 months earlier and there was no sign of problem. The failure was catastrophic, not gradual. When the mechanic called the local Mercedes dealer, the service manager was not surprised and proceeded to outline what parts would be needed to carry out the repair. When I contacted the local Mercedes dealer, myself, they said this wasn-€™t an uncommon problem, but there was not recall or service bulletin on the problem. Was given a rough quote of $5000 to affect the repair. I also contacted Mercedes Benz USA and was told there were no recalls or service bulletins, but they might be able to provide some -€œGoodwill Assistance-€ to offset the expected cost if I had it towed to a MB dealer and got a quote from them. Benzworld.org, an owners forum with over 5 million participants world-wide https://www.benzworld.org/threads/w204-rear-subframes-deterioration.3048088/#post-17965564 has multiple postings about the problem as do other forums including CarProblemZoo.com https://This design/manufacturer defect has had recalls in both Europe and Canada. Why this is not being addressed in the US? This sudden failure is potentially life-threatening.

- Bloomfield Hills, MI, USA

Rear subframe (as recalled in previous years) was completed corroded - failed Virginia inspection - in such poor shape that entire subframe had to be replaced - corrosion riddled the piece so that huge holes resulted in no possibility of welding to fix/supplement weakness - auto repair place had not seen such a weak frame in such a relatively new car. Luckily - no accident occured but could easily have occurred due to corrosion. No other part of vehicle was corroded - so part was manufactured incorrectly (no corrosion control"/shipment from germany issue") - Mercedes Benz has recall for this part in previous model years - pictures of subframe available upon demand

- The Plains, VA, USA