2011 MERCEDES-BENZ C300 Complaints

While driving down the highway at approximately 55mph, my car abruptly swerved left nearly causing an accident with the vehicle in the opposite line. My car was taken to my personal mechanic where he found the rear subframe to be completely broken on the left side due to severe rusting. Luckily the break lines were not damaged during the breakage. I investigated this issue online and it seems to be a very common issue in which no recall has been issued. This is a very serious safety issue that very easily could have resulted in a fatality on myself or other and future failures. It is my understanding that Mercedes Benz has a 30-year corrosion warranty but the subframe is not covered. How can this be?

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. This is a serious safety concern that will happen to 100% of these vehicles. A recall needs to be issued by Mercedes for this immediately. This vehicle has very little rust anywhere except at these connections .

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.

Tried to get alignment and was told rear sub frame is rotted. Must be replaced. Car is garaged. Serviced at dealer. This shouldnt be happening. Car was involved in accident (mainly passenger doors damaged) which triggered us to need to get new tire which alerted us to alignment cant be completed and told to not drive car it's not safe due to rotted subframe.

The subframe and the brake lines are very faulty in this car when it comes to its design. The subframe and brake lines rust easily and are cheaply made for this car. My car break down while driving making it hard to have pressure on the brakes. My incident was around the school area. There were no accidents or collisions Involved. It could happen to adults and children. The dealer never confirmed this problem before selling it to me. Another manufacturer told me about this problem. The car showed warning signs like the braking system and brake fluid. The brake fuel was leaking. The problem appeared when I started the car.

I was driving my 2011 MB C300 40 MPH on a straight suburban road when the light turned red. I applied the brakes and heard a clunk from the rear. Surprisingly, the car swerved with a right turn yaw moment. Normally I enjoy driving my car, but that never happened before. So I tried it again in the next block and it yawed again. That’s not right. My mechanic happened to be just down the road so I pulled in. He told me that the rear subframe had rusted out and the car was unsafe to drive. Furthermore, he would not attempt welding it because the metal is too far gone. A new replacement part is unavailable from the dealership and back ordered from Germany for months. Used part will also be rusty. My car with 77k miles on it is suddenly worthless. Mercedes-Benz “The Best and then Nothing”

The rear subframe rotted and broke as I was driving. I almost got into a bad accident. This apparently is a common & deadly issue that MB is aware of. Unacceptable that there is not a recall.

While driving home last night (with passenger), I experienced a sudden pull to left and wobble\oscillation of the car when I made steering corrections to prevent vehicle from going into oncoming traffic. Car seemed to behave normally except whenever I applied the brakes. I proceeded home, where I inspected for the obvious such as brake calipers, pads. rotors etc. Then I removed the rear left tire. This was due to a clunking sound that seemed to come from that area. Everything looked OK until I saw a front lower suspension part (a plastic covered pressed metal strut connecting the lower part of the wheel\rotor assembly to large U-shaped frame member which had multiple welded attachments and brackets) just hanging there unattached on one (forward) end. The bracket it was bolted to was just sheared off. Looked like it rusted to the point of finally tearing itself off of the frame. There was no warning of this condition either by sensors/lights/etc. or the performance of the vehicle when driving it. The defective braking action was sudden. This is NO SMALL ISSUE! After reading of the numerous reports of this very same problem I have to say I am amazed that NOTHING IS BEING DONE TO PREVENT THE FIRST DEATHS AND INJURIES THAT WILL MOST LIKELY OCCUR FROM THIS. This is a danger to the occupants of the principle vehicle, pedestrians, as well as other vehicles in the immediate vicinity, moving or stationary. This can happen at high speeds, slow speeds, in traffic with other vehicles around the car or humans on sidewalks. I can clearly see that this is not a small repair as it looks like the entire rear assembly would need to be taken apart and reconstructed in order to replace the part. I have also read that this issue is not only common but that it has been recalled in Canada and Europe by Mercedes for repair. I guess we are waiting for the first deaths to occur before our American safety agencies can take action? Really?

Rear suspension crossmember mounting point for one of the control arms broke off allowing control arm to fail. Possible entire wheel assembly could now fail creating dangerous driving conditions especially at higher speeds. Took to a shop and confirmed. Called Mercedes dealership and they said it was not covered by a recall even though in Europe I believe it is. Many websites have said this is an ongoing and common problem.

I have a 2011 Mercedes C300 that I purchased as a Certified Vehicle - this car was purchased at The Mercedes Dealer in Kansas City. I believe I purchased it around 2013 - I have recently found out that the rear sub frame is completely rusted out. I have had the car repaired at my auto shop - Not a MB dealership, as there was not a dealership that was able to see the car in any reasonable amount of time and the car was not safe to drive. The only way I found out about this rusted out subframe was due to the control arm breaking off - This car was very dangerous to drive and in essence, it is probably a good thing that the control arm broke as this could have resulted in a loss of steering on the vehicle and a very dangerous accident! I have been reading online and speaking with MULTIPLE people who have had the same situation with this rear subframe. This is CLEARLY an issue with MB and clearly an issue that they have been made aware of. When I called the NMB service department they were a month out to just look at the car - and the part is on back order I was told - which CLEARLY indicates a lot of these rear sub frames are being replaced. I am attaching various articles / forums online that I just, at a glance, composed a list of. There are a TON of stories of these sub frames rusting out for various models. Seems to be tied mostly to the C300 vehicles. I am attaching pictures of this rusted out subframe and an invoice that I paid to have the car repaired for this issue. The ironic thing is when I was at this auto shop, there was another C300 sitting out front that had just had the same rusted out subframe replaced. Mercedes has a recall in Canada for this SAME issue and other countries have acknowledged this is a major safety issue. A rear subframe should not rust out and leave the driver with no way to steer the car. Mercedes has refused to acknowledge this is an issue in the US.