My car had new brakes installed in the last few months. All of a sudden the car "fishtailed" when applying the brakes. I brought it into my mechanic, Johns Mercedes of Wakefield, Massachusetts, for some routine service and he noticed once he put the car up on the rack that the subframe is completely rotted out due to rust. The brakes were fine. He strongly recommended not driving the car until the part can be replaced. The part is very hard to come by. I called my Mercedes dealership (Herb Chambers Mercedes in Lynnfield, Massachusetts) and Rennan told me that he has seen quite a number of problems lately with rotted subframes in C300s. He said it would cost $5000 to repair IF you could find a part. The parts are incredibly hard to find. In doing research in Mercedes forums, I read that in Germany Mercedes replaces the subframes free of charge, recognizing it is a major safety issue. My mechanic is going to take pictures of the damaged part in question. My car is at his shop now so I don't have pictures to upload at this time. I am going to have him find the part and fix the car at a cost of $4000+.

- Lynnfield, MA, USA

I sensed the rear wheels going into a skid as I braked at low speed. I noticed it first on downhills as I drove on a mountain road which was curvy. It seemed that the car was going to go into a skid. No warning lights came on. I checked the tires were all at the same accurate level which did not change the occurrence. It happened again on flat terrain coming to a quick stop. Like one tire was responding differently than the other in the rear. I asked my mechanic to put it up on the lift so I could make sure I was safe and not causing further damage by driving it until they could fix it. Had the arms cracked off the frame from the wheels while I was driving on a winding mountain road, my life would have been in danger. He came out and said "you need to see this, this car is going nowhere and its lucky that you came in. He pulled back a black cover that was blocking view of the rear sub-frame. One both sides, there was significant rotted through holes. He looked up about a possible recall and came across many people complaining for years on this Model C car having the same issue. It was noted that this issue was a recall and manufacturer repaired issue in Europe. Not here is the US. After reading numerous complaints online from owners, I called the Mercedes Benz dealer (Keeler Motors, Latham, NY) and asked about issues. There are very aware of this issue and quoted me $1400 for the sub-frame and not including many parts that will likely need replacing. With labor at $189 hourly rate. This car is in very good condition, serviced regularly at the Keeler Mercedes Benz dealer department and when we checked it over prior to purchase it was noted how little to no rust there was on the car. Mechanics can easily miss the damage occurring by the black cover over the subframe.

- Chatham, NY, USA

The Rear Subframe is rusted through and cracked making the car almost undriveable. This is a known problem at Mercedes Benz. Nothing else on the vehicle is rusted and has a perfect undercarriage. The vehicle is available for inspection and has been inspected by a reputable German repair facility. There were no warning lamps, messages or other symptoms There's a Mercedes Benz recall for the rear subframe in Canada.

- Carmel, IN, USA

While my car was being inspected at the Mercedes dealer from who I purchased the car, I was informed that the rear subframe was rusting out, needed to be replaced immediately (at the cost of $4250) as it is unsafe to drive and that the result could be catastrophic if I continued to drive it. They explained that they are having this problem with other C300 models in the US, Canada and Germany, but there has not been a recall in the USA. They told me that it might be the road salt as this is only happening in the North East. If this were true than I would think other parts of the undercarriage would be rusted or this would occur in other models too. They are well aware of this issue but have neglected to contact owners therefore putting my life and the life of my family at risk. The NHTSA needs to investigate and recall these vehicles immediately before someone is killed. Seems to me they are using sub standard materials and while having knowledge of this issue, should be held accountable. Thank You.

- Bristol, PA, USA

I was driving on the highway i hit the brakes as traffic was starting to build up and the car veered into the right lane and all of a sudden and almost got hit by a tractor trailer. It felt so scary, weird when hitting the brakes after that. I took it to my mechanic immediately and he said the rear subframe is rotted out and DO NOT DRIVE THIS CAR!!!!!!!!! I asked please get me an estimate on how much to fix. He called me later in the day and said it was a 8 month wait for the part and the Mercedes dealer said it is a VERY VERY VERY common problem on these cars. There are Thousands and thousands. There is a defect when manufactured and MERCEDES does not want to do a recall or step up to the plate in the United States. There is a recall in Canada and Europe that replaces the part. What are they waiting for till some gets hurt seriously or killed. Now i do not have a car to use for who knows how long and Mercedes should be ashamed. Please advise. This is a real scary safety issue. Please advise. Thank you [XXX]. INFORMATION Redacted PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).

- Huntington Station, NY, USA

Subframe corrosion, no accident but dangerous and common issue with Mercedes Benz cars

- Paterson , NJ, USA

The contact owns a 2013 Mercedes-Benz C300. The contact stated that while his wife was driving approximately 35 MPH and attempting to abruptly stop the vehicle to avoid a crash, the vehicle suddenly drifted into the opposite lane while depressing the brake pedal. Upon inspection, it was discovered that the rear control arms had failed. The vehicle was driven to the local mechanic who diagnosed that the failure was due to severe subframe corrosion. The contact was informed that the rear subframe and rear control arms needed to be replaced. The vehicle was not yet repaired. The local dealer and manufacturer were notified of the failure. The failure mileage was 86,000.

- Bensalem, PA, USA

Filing complaint for my 2013 Mercedes C300. I was informed by the dealership this vehicle has a rusted out rear subframe and the vehicle is no longer operable. This is a very common and serious safety issue, and the Mercedes dealership is refusing to cover the cost of the repair. Please help!

- Indianapolis, IN, USA

While driving on highway, started to slowdown on exit. Vehicle rear end felt waiving side to side. Had vehicle checked with local mechanic. Reported rear subframe rusted and split. Advised not to drive & replace the subframe. Visited MB dealer service. Informed it is a known problem and a safety problem. Can repair when part is re-stock in January 2023"? $4,000 + Research online. Plenty reports in forums with same problem. Why there is not a safety recall"

- Cranston , RI, USA

August 30,2022 local Mercedes Benz dealer stated that their inspection found that the rear sub frame was rusted and needed to be replaced (estimated cost $4,699.88). I had two other independent repair shops confirm the sub frame condition.My car had 78,753 miles on it at time of discovery of sub frame corrosion condition. My independent repair shop says that OEM sub frames are back ordered with no estimate of when one would be available. Internet searches and discussion with independent repair shops indicate the rear sub frame corrosion, and structural failures, are a common problem.Structural failures are a serious safety hazard and this defect should be the subject of an NHTSA investigation and recall and replacement by Mercedes Benz. Structural suspension parts should not corrode and fail after only 78,000 miles on cars driven in normal conditions.

- Montgomery, OH, USA

The rear suspension frame was rusted, and the suspension rusted off the frame through normal wear and tear (no potholes, incidents, etc). Left side rusted off, Right side is on its way. Brake distance was increased and suddenly braking on the highway resulted in back of car swerving slightly, almost hit a truck that suddenly merged into my lane. This was discovered during an MD state inspection, I called 6 dealerships in the area, and all were familiar with the issue with this chassis. I got two estimates saying the same problem. This forum shows that there are many more like me, and even in the UK dealerships are doing replacement free of charge due to how widespread it is: https://www.benzworld.org/threads/w204-rear-subframes-deterioration.3048088/ The part has not been inspected by the manufacturer/police/insurance inspector. There were no warning lights or any alerts on my dash indicating this issue, I only found out bc I just so happened to need to do an MD state inspection, and I had been hearing a squeaking noise. Also, my brake distance was longer, and my car swerved a little under sudden braking on a dry sunny day.

- College Park, MD, USA

The contact owns a 2013 Mercedes-Benz C300. The contact stated while driving approximately 65 MPH, the vehicle started shuddering inadvertently, almost causing the contact to lose control of the steering wheel. The contact was able to veer to the side of the road. The vehicle was towed to a certified independent mechanic who diagnosed that the driver's side rear subframe was severely corroded and fractured. The vehicle was not repaired. The dealer was not notified of the failure. The manufacturer was made aware of the failure and a case was opened. The approximate failure mileage was 95,000.

- Chelmsford, MA, USA

Rear subframe cracked; car has less than 95,000 miles and looks great. My two children of driving age were using the vehicle at the time, driving others as well. Fortunately, I happened to drive it not longer after the issue and took it to the shop immediately. They put it on the lift and saw that the rear subframe was cracked all the way through. As it turns out, it is becoming very common on this make/model--and it is nearly impossible to get a replacement. Mercedes Benz told me maybe sometime in 2023. In addition to having it inspected, I have since been in contact with several dealers and mechanics. Results are invariable: the part is in extremely high demand, Mercedes cannot fill the demand, and the wait is indefinite but long. There were no warning lamps, messages or other symptoms of the problem. In addition to the inconvenience, the car was very dangerous to drive. I am thankful that my son did not seriously injure himself or others while driving. The crack renders the car unstable at anything but the slowest speeds. When one brakes at any speed over about 20-25 mph, the car pulls violently to one side. Simply braking alone could cause a major, even fatal, accident. And any emergency maneuver could be disastrous. The car has been garaged since June awaiting a replacement that I am told will cost between $4000 and $6000! I am left with a vehicle that runs very well--but is unsafe to drive on a public roadway--and no way to repair it. Moreover, Mercedes cannot tell me when the part may become available (likely sometime in 2023).

- Avon, CT, USA

Brought my car to the dealership because I was hearing a noise when going over bumps. Also noticed some instability when braking and driving at highway speeds. Dealer informed my my subframe had rusted and told me the car was unsafe to drive.

- Cincinnati, OH, USA

Rear subframe and rear wheel control arm separated and corroded. Car not safe to drive. 2013 model with 31,000 miles, always garaged and maintained.

- Scarsdale, NY, USA

The rear subframe on the car is completely rusted. I get an oil change and a inspection of the car done at the dealer each year. Nobody mentioned to me that the rear subframe is rusted and is about to crack and fall apart. Was driving home from work when I suddenly had to stop and the whole car shifted to the right almost causing me to crash. Drove home and noticed a noise every time I hit the brakes. The next day took it to a mechanic and he showed me that the subframe cracked and fell apart. I know this is a big issue in europe and the dealers change it free of charge since it is on a recall, but nothing in the usa after several complaints from drivers. Do something about this!

- Elmwood Park , IL, USA

I had noticed that my car was starting to pull to the side when braking. I took it in to my authorized dealer, where I always have it serviced and maintained, and I was told that the rear sub-frame bracket was broken off at the left rear lower control arm attachment point. The rear sub-frame and left rear lower control arm needs to be replaced. I was told that the car was absolutely not safe to drive. I have always taken great care to maintain the vehicle, and it has always been stored in a garage. There were no warning signs prior to the failure, and I was very surprised to hear that the sub-frame had rusted out since there is no rust anywhere else on the vehicle.

- Windsor, WI, USA

The left rear subframe is torn and severely rusted. The left rear arm also needs to be replaced because it is essentially not connected to anything which makes the car not safe to drive. I took the car to an independent shop and was told not to drive the car any longer. I had to have the car towed to my home. I was made aware that this is a common issue In Mercedes C300 and Mercedes US has refused to issue a recall although in Canada a recall has been issued on this particular part. I was driving on the highway with my 1 yr old in the backseat when my car started to pull side to side. The car felt out of control. There were no warning indicators about this issue so I wasn-??t sure what was going on. Im happy I followed my instincts and had the car looked at. I am now faced with purchasing a new car or having the car repaired for several thousand dollars. I have had the car for six years without issue and I-??m told that this is a manufacturer defect.

- Thorndale , PA, USA

So I took my car to get new tires and the tech told me that my rear subfram was rusted and cracked, unsafe to drive. I called mercedes and they asked to take it to the dealership and get a quote. I did this and there response was to do nothing.this issue has been recalled in Germany and also Canada. But nothing done in United States. This is a serious safety issue.let's say I never got my tires and never found out and was traveling 70mph down the freeway and had to hit the brakes hard for whatever reason and this part fails and breaks. Everyone in my car and whoever else my car collides into life's would most definitely be in danger

- Woodbridge, VA, USA

The driver side suspension mount to the rear subframe has rusted through. While applying the brakes the car pulled radically to the left almost causing me to lose control. This is a known issue from what I can determine but Mercedes has refused to issue a recall. The car cannot be driven until this is fixed.

- Newark, DE, USA