Which parts fail
Components named in complaints (struts, shocks, control arms, ball joints, springs).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2011 Mercedes-Benz C300 owners, lightly cleaned up (personal details are redacted by NHTSA).
I was driving down the road when a deer ran out into the roadway ahead of me. I applied the brake firmly and hear a "pop" and the car suddenly changed lanes. I was able to recover without much of an incident but applying the brakes from that point on caused the car to "steer" into a new direction. I took the vehicle out to a friends farm and jacked it up to find that on this car with zero other corrosion issues that the mounting point for one of the rear suspension arms had rusted at the weld and broken off the sub frame. I should note that the rest of the underbody was inspected and the rear subframe is the only place that has any corrosion. Research into this issue over the past few months has lead me to countless people being affected by the same issues. …
The contact owns a 2011 Mercedes-Benz C300. The contact stated while driving 25 MPH, the contact was going around a corner when he noticed a vehicle in front. The contact depressed on the brake pedal and the vehicle violently jerked and stop. The contact stated that the steering wheel was leaning towards the left. The contact was able to drive the vehicle to his residence. The following day the contact took the vehicle to an independent mechanic who inspected the vehicle and diagnosed the failure as a fractured and detached rear control arm due to corrosion of the undercarriage and subframe. The vehicle was towed to a local dealer to be repaired however, the contact declined the repair due to cost. The vehicle was not repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 82,000.
The contact owns a 2011 Mercedes Benz C300. The contact stated while driving 35 MPH, the brake pedal was depressed abruptly and the vehicle fishtailed off the road. The contact stated no warning light was illuminated. The contact was able to continue driving to her destination. The contact took the vehicle to an independent mechanic and was informed that the brake calipers needed to be replaced. The vehicle was not repaired. The contact called the local dealer and made them aware of the failure. The contact continued to experience the failure. The contact took the vehicle back to the independent mechanic and was informed that the subframe was corroded. The vehicle was not repaired. The manufacturer had not been informed of the failure. The failure mileage was approximately 160,000.
The contact owns a 2011 Mercedes-Benz C300. The contact stated that while driving at an undisclosed speed, the rear driver's and passenger's side wheels swayed left to right, and the rear driver's side wheel detached from the suspension. No warning light was illuminated. The vehicle was taken to a repair shop where it was diagnosed that the rear subframe was rusted and needed to be replaced. The dealer was notified of the failure and the contact was scheduled an appointment. The manufacturer was notified of the failure and the contact was awaiting an estimate. The contact was provided a case number. The failure mileage was 88,640.
The contact owns a 2011 Mercedes-Benz C300. The contact stated while driving approximately 60 MPH, the brake pedal was depressed, and the rear end of the vehicle pushed out. The contact looked underneath the vehicle and noticed that the subframe was rusted. The vehicle was taken to an independent mechanic who informed the contact that the control arm had detached. The contact called the local dealer, but the vehicle was not diagnosed or repaired. The manufacturer was contacted but no additional assistance was provided. The failure mileage was approximately 105,000.
The contact owns a 2011 Mercedes-Benz C300. The contact son stated while driving at various speeds, the rear of the vehicle would sway while braking. The contact stated no warning light was illuminated. The vehicle was taken to an independent mechanic and was diagnosed with needing the subframe to be replaced. The vehicle was not repaired. The manufacturer was informed of the failure and informed the contact that to take the vehicle to an authorized dealer for assistance. The failure mileage was approximately 119,000.
I just purchased a 2011 Mercedes C300. I was told that for the past 2-3 years the vehicle would constantly bald out the rear 2 tires and would need replaced every 3 months. As I was driving the vehicle I noticed that the rear tires would make weird noises as if it was hutting something. Upon further investigation the rear sub frame is rotted, which based on research appears to be a very common problem with these vehicles. The rear sub frame is rotted in which caused the lower control arms to completely rot off of the frame posing as a serious safety issue for me when driving with my children and a safety issues for others when I drive on the road. On top of that due to the lower control arms completely rotting off the frame it caused the control arms to hit the gas tank which could catch the car on fire. Mercedes has refused to issue this as a recall in due part to their negligence. …
I was teaching my 16 year old son how to drive when he got his learners permit . When we got onto the highway a car cut him off and he had to apply a firm steady brake . When breaking the car swerved from the rear into the other lane , nearly striking another vehicle . This also resulted in a loss of control when applying heavy breaking after I had him pull over and I took control of the vehicle once I was able to get the car to the shop I pulled the rear wheel s off and inspected the brakes , which were found to be in good condition . I looked around the vehicle and noticed where the rear driver side subframe connected to the control arm broke off from a manufacturer defective weld or poor selection of materials . component. Upon inspection both sides are perforated and have lost structural integrity. Many other vehicles of the model type have reported similar issues online. …
Due to design flaw and/or poor material quality, I have a car with less than 100,000 miles that has completely rusted thru the subframe. I was told by a Mercedes Benz dealer that this is a common problem with this car. The cost of repair was quoted at $4000. This was only discovered due to the MB mechanic removing the covers on on the subframe discovering the rust. I was told it would not pass inspection but it just did in February at the dealer I bought the car from. I told the MB dealer this and they said they probably didnt know the covers need removed to see the issue. This is a huge safety issue that people who drive these cars are probably not aware of. Failure of this area could cause loss of control as this is a critical suspension link responsible for maintaining steering direction of the rear wheels. Once these linkages fail the driver will lose control of the car. …
What component or system failed or malfunctioned, and is it available for inspection upon request? Rear subframe has rusted out and left side arm has separated- my car has been routinely maintained and primarily housed in garaged parking. It does not have a history of flood or water damage. How was your safety or the safety of others put at risk? My steering and breaking was impacted even at low speeds < 30 MPH. Has the problem been reproduced or confirmed by a dealer or independent service center? - Vehicle failed a Maryland state safety inspection and was deemed unsafe to drive. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? Yes, inspected by Maryland state certified safety inspector Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? …
Suspension complaints in other C300 years
Frequently asked questions
How common are suspension problems on the 2011 Mercedes-Benz C300?
NHTSA has 60 complaints about the suspension of the 2011 Mercedes-Benz C300, 13% of the model year's 480 complaints. The component named most often is subframe/mounting bracket (3 mentions).
Is there a recall for 2011 Mercedes-Benz C300 suspension problems?
No. NHTSA lists no suspension recall for the 2011 Mercedes-Benz C300, though it has 6 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2011 Mercedes-Benz C300 suspension problems start?
Half of the complaints with a recorded mileage happened before about 93,000 miles.
Is it dangerous?
Owners linked 0 crashes, 0 fires and 3 injuries to suspension problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.