Suspension Problems of Mercedes Benz C300 - part 1

Mercedes of danbury replaced the rear sub frame code 3441 47, since my mechanic (newtown auto repair) told me that the front subframe is in real bad shape, rotten/rusted, that it is dangerous to drive the car in this condition since the wheel and steering components are part and attached to it, the car would be out of control and all over the road any of these components fail and pull / brake away from the rusted out sub frame. When I brought the car in was under the impression that Mercedes Benz would replace front and back sub frames. But now they informed me of only recall on rear subframe, rear subframe will let go wheels will collapse, front controls the car and failing could kill people and total the car. Frames.

See all problems of the 2012 Mercedes Benz C300 🔎.

Rear subframe completely rusted out. While driving on the hwy I heard a loud noise, a couple minutes later I hit the brakes to slow down to get off my exit and after pressing the brakes the car instantly fishtailed sending me sideways across 2 lanes of traffic. Luckily no one was injured or killed. I’ve seen that the car manufacturer was replacing this issue on models 2008-2015. My vehicle is a 2015 and they are telling me my vehicle is not covered for the issue. The car is not drivable and mercedes needs to be held accountable. A critical component such as rear subframe completely rusting out in just under 10 years is unheard of and I can’t afford to pay 10k to fix it. Please help.

See all problems of the 2015 Mercedes Benz C300 🔎.

Rear subframe rusted out, car is not safe to drive.

There is a recall for 2008-2015 mercades benz c-300 c/w204. This recall talks about the rear subframe rusting out early on this car. We have a 2015 C300 c/w205. This car is seeing the same early rust seen in the other c-300. The dealership is refusing to do right by the warranty because it is a c/w205 even thought this is a known problem for this year and type of car. I am making this because it should be extended to all C300 2008-2015 cause they all use the same subframe. They changed the subframes and the look of the c-300 starting in 2016. It also would appear that the rust is coming from the inside of the subframe making we wonder how bad it is on the inside if it is making its way to the outside of it. I believe water penetrates into the rear subframe has no drainage and begins to rust. Also we take the car to the dealer every 5 ish months and this last service is the first we have seen of this.

Got a car from the dealer soon weeks after the rear subframe was so corroded alignment was able to get done and was snapped on both sides airbag light came on doesn’t go away and the rear right brake like started using the fog light as a turn signal.

See all problems of the 2010 Mercedes Benz C300 🔎.

Due to the corrosion in the rear subframe both side of lower control arms snapped the tires to the car are wearing out due to the corrosion in rear subframe and it’s was also hitting my gas tank if I was to go over any holes which can cause a bigger issue.

The rear subframe on this vehicle is rusted and has hole in it. The sub frame requires replacement. The sub frame was inspected by the mercedes-benz dealership, euro motorcars in germantown, MD and they recommended that the sub frame should be replaced. There is an extended warranty that has been issued by mercedes-benz for the model year and model (2008-2015 c-class sedan/coupe). However, mercedes-benz decline to cover the cost of the repair stating that my VIN is not part of that warranty. This is a well documented safety issue and I believe that mercedes-benz should include my VIN in that extended warranty and replaced the subframe on my car.

Failed/malfunctioned component: rear subframe (structural/chassis component) exhibited advanced corrosion (perforation/rust-through), compromising structural integrity and alignment/handling. Availability for inspection: yes. The vehicle and the subframe are available for inspection upon request. I can provide photos, videos, and repair estimates if needed. The corroded subframe is fracture and detach suspension mounting points, which may lead sudden loss of vehicle stability or control (especially during braking, cornering, or over bumps). Unpredictable alignment changes causing pulling, vibration, or abnormal tire wear that can escalate into a loss-of-control event. Increased stopping distance and potential for wheel misalignment or collapse, raising the risk of a crash involving occupants and other road users. I limited driving/use due to the risk; issue is a structural safety concern rather than cosmetic. Confirmation: yes on multiple visits since oct 2023 -yes—diagnosed and documented by mercedes-benz of silver spring on oct 2 2023, Nov 2023 and Dec 2025. Technician confirmed severe corrosion/rust perforation on the rear subframe requiring replacement. No no.

Rear subframe crossmember rotting, needs replacement. It seems to be a common problem with this vehicle and the assumption by most professional is that it a faulty part supplied by a third party to mercedes. The rest of the cars undercarriage is pristine, making me wonder why just this one part would rust out.

Rear-subframe corrosion at the lower-control-arm mounts has progressed to the point where both arms have play and produce loud metallic bangs while braking or turning at low speed. Two independent shops lifted the car, documented flaking rust around the bushing sleeves, and advised the subframe is structurally compromised and could let a control arm detach under load. The corroded subframe remains installed and can be inspected on request. Safety risk: a detached rear control arm would cause sudden, unpredictable steering and loss of control. The vehicle already pulls right under braking, and feels very unstable in curves problem has been reproduced and photographed by two independent repair facilities. No manufacturer representative has inspected the vehicle so far. Additional component failures possibly linked to the same progressive chassis stress: premature wear of both front cv axles; timing-chain stretch with worn guides; slack oil-pump chain; upper & lower oil-pan gasket leaks; water-pump seepage; right engine-mount collapse; persistent misfire traced to a loose intake-hose clamp; transmission-cooler hose clip released under pressure, dumping all atf and destroying the automatic transmission; excessive play in all four lower control-arm bushings. The transmission and the other components were replaced 1-2 months before the subframe bro history: a faint clank from the rear suspension first appeared roughly three years into ownership. Dealer service dismissed it as “normal noise,” and warranty would not cover “loud clanks,” so the issue went unaddressed. The noise has grown steadily into the current condition, suggesting long-term subframe corrosion that was never inspected or remediated. No collision, flood, or off-road use; the car has typical northeast winter-salt exposure. The failure pattern matches subframe-corrosion cases already acknowledged by the manufacturer on this model, although this serial number is not yet included in the official campaign.

Unknown.

See all problems of the 2017 Mercedes Benz C300 🔎.

Rear subframe broke while driving- made stearing/controlling/breaking car very difficult & dangerous. . . . After reviewing on internet- mb is aware of this problem.

The contact owns a 2015 mercedes-benz C300. The contact stated that upon taking the vehicle to an independent mechanic for a routine maintenance check, the contact was informed that there was severe corrosion on the subframe of the vehicle. The contact was informed that the vehicle was unsafe to drive and that several failures might occur due to the failure. The contact stated that recently, while depressing the brake pedal, the vehicle swerved, and the contact lost control of the vehicle. Upon investigation, the contact discovered that there was a warranty on the vehicle related to the failure. The manufacturer was notified of the failure, and the contact was informed that the vehicle was no longer covered under the warranty. The vehicle was not repaired. The failure mileage was approximately 110,000.

Recently my mercedes has been pulling and swaying to the side while breaking even at low speeds. Yesterday I got my 2 front tires replaced and asked them to take a look at what could be causing my rear end to pull. When I returned to pick up my car they informed me my rear subframe was completely decayed/rusted through and not safe to continue driving.

See all problems of the 2013 Mercedes Benz C300 🔎.

I took the car for annual maintenance to mercedes-benz dealership. After routine check up they came back to report rusty rear subframe and told me that needs to be replaced. However this part is really expensive and models from 2008 to 2015 C300 had the same issue(premature rust) and they all received extended warranty from mercedes-benz for free replacement. I wanted to report this safety issue for C300 model including mine that is not covered under extended warranty.

Took the car in for an oil change and asked them to look at the brakes and rear as there was a strange noise. Vehicle was inspected and found the entire subframe is rotted. Was advised this is a common problem with mercedes and there were some recalls. Unfortunately no open recall on this vehicle and it is now not driveable as this is a safety risk. Car has been driven 60 miles/day for the past 3 months and could have had serious consequences.

The left rear subframe separated from the main frame causing the car to pull to the left when braking. I had an episode where I was stopping for a traffic light and the car started fishtailing and I almost lost control of the car. Following this episode, I took the car to a mechanic who advised me that the car was unsafe to drive. My mechanic also told me that he has repaired a number of these vehicle with the same problem, and that Mercedes Benz has extended their warranty from 4 years 50,000 miles to 20 years unlimited mileage. They did the extension after someone filed a class action suit in georgia about the problem. The vehicle is presently at a mercedes dealer awaiting the new subframe.

See all problems of the 2014 Mercedes Benz C300 🔎.

On January 21,2025, I had an appointment for an inspection at Mercedes Benz of smithtown, the dealership I use. I was informed that my car required replacement of a rotted rear subframe. A hole had rotted through, causing the car to "fail inspection and was not safe" to drive. I was provided a video showing the damage. There was a recall in effect however, my VIN # was not included and it’s status has not changed. The 2015 c-class sedan/coupe VIN # [xxx] , which was neglected to be included in the recall covers 2008-2015 c-class sedan/coupes, regarding rotted rear subframe. Mbusa extended the vehicle warranty 4 yrs/ 50,000 miles to 20 yrs/unlimited miles. However, I do not qualify for reimbursement of $4,014. 92, because my VIN # was left off the list. Mercedes customer assistant center states they can't help, has to be included by NHTSA, when I said they cannot add a VIN #. I was then told, it has to come from the head office in germany. Nothing like getting a run around not what I expected from Mercedes Benz USA, information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

The contact owns a 2010 mercedes-benz C300w. The vehicle was taken to the dealer for an alignment. The contact was later informed that the wheel alignment was not fully completed due to extensive corrosion on the subframe. The contact picked up the vehicle and upon investigation discovered that there was a warranty on the vehicle for the corrosion of the subframe. An appointment was scheduled, and the vehicle was taken to the dealer where it remained for two weeks. The contact was later informed that the condition of the vehicle did not reach the warranty standards for repair. The vehicle remained in the possession of the dealer unrepaired. The manufacturer was notified of the failure and the contact was informed that dealers were independently owned and made their own decisions on warranty repairs. The failure mileage was approximately 63,000.

Subframe rusted resulting in failure of left rear suspension mount causing dangerous loss of control of car under braking.

See all problems of the 2011 Mercedes Benz C300 🔎.

In October 2024, the rear subframe was replaced due to rust perforation in the area of the suspension arm mounting bracket. I had no warning. The car was in for routine service at Mercedes Benz of new london. It had rusted from the inside out and was considered unsafe to drive by the mercedes service advisor. I could have had a serious accident! I had no choice but to replace the subframe as it is my only vehicle. Shockingly I learned many others have had this issue with various mercedes models/years and that Mercedes Benz knows of this serious safety problem and there is a class action lawsuit pending but subframe replacement is not covered under warranty by Mercedes Benz, so the cost was mine to bear.

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. Customers cannot afford to pay $5000 for a rotted subframe due to negligence from mercedes. Please research how many vehicles have had rotted subframes for this vehicle. In germany they will repair the rotted subframe free of charge. Mercedes needs to be held accountable for risking peoples lives.

On several instances of breaking, my 2013 Mercedes Benz C300 pulls hard to the right and becomes very unstable. I assumed it was a brake problem by the way the car drove. I took it to my mechanic, who immediately identified the rear subframe had rusted so much that a control arm had broken loose from the subframe. The rear subframe acts as a foundation for the rear suspension and holds the backend together. Fortunately I was able to get this diagnosed prior to a serious accident. The car gets very unstable, especially at higher speeds, when braking. There are no warning lights that will catch this. This problem absolutely places both passengers and other cars on the road at risk of a collision when braking, especially on the highway at higher speeds. I am going to contact a local Mercedes Benz dealer to evaluate replacement of the damaged parts to ensure the car is safe to drive following repair. Based on the links below, it sounds like a known issue at Mercedes Benz. I was never notified of any issues or from prior service visits, or via mail notice from the manufacturer. My mechanic was shocked, to say the least. Hoping mb will take care of this dangerous problem without hassle. See: [xxx] [xxx] [xxx] information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

Rotted rear sub frame due to poor design retaining water.

The subframe has developed extensive rust and corrosion, which I believe is a result of faulty manufacturing. This corrosion has severely compromised the structural integrity of the subframe, posing a serious safety risk. The corrosion appears to be inherent to the materials or design used in the manufacturing process, leading to the rapid deterioration of the subframe. There are also no warning lights or failure indicators for this issue. As a result, the subframe is at risk of collapsing, which could cause catastrophic failure of the vehicle's suspension and steering systems. This situation creates an immediate danger to both the occupants of the vehicle and others on the road.

My car (VIN [xxx] ) a 2015 mercedes C300 is experiencing the same premature rusting on the subframe. I was told that while a lot of mercedes are covered, mine is not for some reason but I'm at the same risk for the subframe getting holes in it and wheels breaking off. I only have 78,000 miles on my car, only have it serviced at the dealer and it has been garaged parked. This type of damage is not typical for a car that has been this well cared for and for the amount it has been driven. I called mercedes to honor the $5600 or to extend the warranty should it have to be replaced and they said to file a claim here. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

The defect is a rusted rear subframe with large holes that will break and cause wheels to become detached and lost control of the vehicle. The issue was identified and repaired by an authorized mercedes dealership. Additionally, an authorized mercedes mechanic provided video of my vehicle showing a rusted rear subframe with huge holes on both sides of the vehicle. He also stated the vehicle is unsafe to drive. Mercedes has issued an extended warranty on this same exact issue but only to certain vins.

My 2012 C300 has a rotted rear subframe making the car not able to be driven. It has major ,life threatening, costly damage and this issue already has a recall all over the world but not in the united states. If I can get the assistance to pay this repair, it will be gladly appreciated.

The entire rear subframe of any w205 body model including but not limited to the c class from 2009-2014, cl class, sl, class etc. Suffers admittedly from mb USA, premature rust, deterioration etc. There is an active recall for these same models in canada and all of europe but not the USA. My garage kept 2009 C300 has suffered extensive rear end damage from a factory defect that mercedes refuses to recognize in the continental u. S. But will admit the same issues occurred in the eu and canada. Keeler mercedes, USA, of colonie new york, stated they completed my subframe repair under the mb rear subframe extended warranty. The vehicle was driven home and inspected only to find out keeler mercedes of NY did not replace this crucial safety component under mb-USA extended warranty issued for this defect. This is pure negligence. When asked why the subframe wasn’t replaced as the work order stated it did, they stated “a mix up in paper work” I believe mercedes-benz USA and keeler mercedes of new york conspired together to push this massive safety defect aside and lie about completing the work in fear of the payment from warranty not being worth the labor hours required by the technicians. This oversight could have been a multi million dollar lawsuit if any injury was sustained after said repairs were done in belief the vehicle was safe to drive. Keeler mercedes’ has also had this vehicle in their possession from June 14th 2024, to todays date, July 5th 2024 with no word on when repairs to subframe will be completed. Subframe replacement stated on mb website states it is an 8 hour labor job. We’re on day 18 now. Major safety issue and shady dealing by dealership.

See all problems of the 2009 Mercedes Benz C300 🔎.

Took car in for oil change and was informed that car should not be driven because rear subframe had rotted thru and rear link was completly unattached and hitting gas tank. Havent had a response from 2 dealerships this car is unstable and hitting the brakes requires a lot of attention to keep on road.

Took my car for a doorknob repair and was told the whole subframe is rotted. They told me not to drive the car on the highway. The car brakes very hard to the right and always goes right while making cranking noises. Car feels very unsafe. I paid a lot of money for this and own a 2012 C300 4matic.

The contact owns a 2012 mercedes-benz C300. The contact stated while driving at an undisclosed speed, he heard an abnormal sound coming from the rear of the vehicle, prompting him to pull to the shoulder of the roadway. After a visual inspection, the contact observed that both trailing arms had become detached. No warning lights were illuminated. The vehicle was taken to an independent mechanic, who determined that extensive frame corrosion had caused both trailing arms to detach. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 143,000.

After noticing brake fluid leaking I took my car to a local automotive shop and when he raised it to checkout the break line when he found the leak from the rust . He noticed a more serious problem that the subframe was rusted out on each side. He told me to contact mercedes immediately because the car is unsafe to drive.

Subframe rusted and broke. It is available for inspection. Burlington mercedes inspected the vehicle and told me it was not safe to drive. Mercedes-benz USA is aware of the problem. They issued a letter extending the warranty covering only the subframe to twenty years and unlimited miles. Burlington mercedes refused to do the subframe replacement without installing all new arms, which are currently not damaged. The cost to install all new arms is $2826. 54. Mercedes-benz USA is offering a warranty extension that their dealerships refuse to honor. This needs to be turned into a recall instead of a warranty extension. This subframe issue is dangerous. It affects mercedes vehicles dating back to 2005 and encompasses many of their models including: slk- class, cls-class, sl-class c-class sedan/coupe, glk-class e-class sedan/wagon, e-class coupe/cabrio.

Recently I was driving and heard a knocking/creaking noise in the left rear. When braking I felt as though I was going to lose control of the vehicle. . . Vehicle appeared to fishtail and pull to the left. I first noticed it on [xxx] when I was driving on the highway in excess of 60 mph. On [xxx] I brought it to my mechanic (genesee auto repair, 40 liberty street, salem, nh (603)898-1899) and my mechanic informed me that the left rear subframe had rotted out and told me that I should not be driving the car. There were no warning lamps or messages indicating there was a problem. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).