skullbox15

I got a letter today from MB USA stating they have extended the "rear subframe" under warranty for 20 years/unlimited miles. Also covers the SLK, CLS, SL GLK and E class for various years. As the letter states:

"In the event the rear subframe experiences corrosion with perforation (holes), this warranty extension applies to the replacement of the rear subframe under the standard warranty terms and conditions of the New Vehicle Limited Warranty"

Does that mean they figured out they didn't treat the metal properly and these things are rusting out? I assume we're talking steel but could it be aluminum since the mentioned corrosion? I'm not sure what the rear subframe actually is... the are around the rear diff?

C63Dave

Just received the same letter in the mail last week. Happy I got one because when I called the MB dealer two weeks ago for more details, the advisor on the phone claimed she had no knowledge of any recall.

From the class action lawsuit findings: "A proposed class action alleges a number of 2010-2022 model year Mercedes-Benz vehicles have subframes that can prematurely rust or corrode “from the inside out,” leaving the critical component “structurally unstable and prone to failure. The 150-page lawsuit out of Georgia explains that a subframe attaches to a vehicle’s frame/chassis on the back undercarriage and provides stiff mounting points for the car’s suspension and driveline components. The rear subframe must be “stiff and resilient” as it’s crucial to securing a vehicle’s rear suspension and rear wheels to the car, the filing says.According to the complaint, a defect allows water and salt to collect on the interior of the Mercedes subframes at issue and corrode the frame from the inside out, making the damage difficult for a mechanic to detect during a routine inspection. The subframes, which should last the life of a vehicle without replacement, may have also been treated with an “inadequate type or amount” of rust coating, the case claims.

The complaint says the Mercedes subframe defect can harm the drivability of affected vehicle models and cause brake lines, suspension springs, the rear axle and the exhaust system to corrode severely and prematurely, especially near the attachment points for suspension components such as control arms, the main stabilizing force of a vehicle’s suspension. According to the suit, a corroded rear subframe is likely to crack when a driver hits a pothole or needs to brake suddenly and can cause the vehicle’s rear suspension to become destabilized.

If a Mercedes subframe, also called a suspension cross-member or axle carrier, fails entirely, it can cause a driver to suddenly and unexpectedly lose control while driving, the suit states. When this happens, the rear of a vehicle can fishtail, especially while braking; the vehicle can suddenly veer to one side, potentially into another lane of traffic; or the driver could completely lose control of the car, the case says.

“The defective subframes in the Class Vehicles pose a material safety risk, and therefore render the vehicles unfit for their intended purpose,” the suit alleges, noting that the problem has led authorized Mercedes dealers and independent mechanics alike to advise owners and lessees to not drive their vehicles, especially at high speeds. “Many Class Vehicle owners are therefore left with vehicles too dangerous to drive, especially at typical highway speeds.”

According to the case, the vehicle models affected by the subframe defect include, but may not be limited to, the 2010-2022 Mercedes-Benz C-Class, 2010-2022 Mercedes-Benz E-Class, 2010-2015 Mercedes-Benz GLK-Class, 2010-2022 Mercedes-Benz G-Class, 2010-2022 Mercedes-Benz CLS-Class, 2010- 2020 Mercedes-Benz SLK/SLC-Class, and 2010-2022 Mercedes-Benz SL-Class."
I will be working to get my subframe replacement scheduled and hope it can improve the car's handling.

-C63Dave

BLKROKT

The way I read it, unless you have holes in your subframe from corrosion, you’re not getting a subframe replacement. This wasn’t a recall. It’s a warranty extension. That means the occurrence of this is exceedingly rare.

AMGSPY

What BLKROKT said. That's what I got out of it.

lo-fi

I thought I was on the e46 m3 forum for a second.... lol (although technically the issue on the e46 was the rear axle carrier panel).

deadlyvt

Yeah it's not a recall. It's a warranty extension like mentioned above. If you take it in and you don't have corrosion they aren't replacing it .

roadtalontsi

Basically if you live in the rust belt and don't take care of your vehicle to clean harsh chemicals off regularly and it's a huge pos winter beater, MB will foot the bill on the subframe for your ignorance even after over a decade of abuse, and athough you're the 5th owner and didn't own or buy it under the original 4yr/50k warranty. Reverse darwinsim at its finest.

Adi-Benz

We've had a ton of these in the regular w204 section, but I'd imagine they get used more than the AMG's and year round as well.

Spanky63

Am a tech at MB. You guys are right, if there's no corrosion... we're not touching it.

Accidental L8 apex

A coworker who put many miles on his 2010 c300 in upper Michigan is about to get reimbursed almost $3k for his replacement he had done 10 days before the announcement. 👍

JustLooking

Under hard braking two days ago on a highway offramp the car squatted and swerved. I thought maybe a caliper locked up or something, even though I just had everything looked at 5000mi ago (2014 C3004, 90K miles). Started making some clunking noises upon release of brake while driving yesterday, so I brought it to an indy shop today. I just spent 285$ on a weld job to fix the cracked section. I never got any letter about it. Will be following up with MB at my next service to see about replacement, thanks for all the posts here to document the issue, I wouldn't have ever found out about it!

notlimahrelyt

I recently started experiencing a slight vibration at higher speeds. While understanding that this could be many things, I figured since this extended warranty is available, I should go get the car checked out to see if it's eligible. MB Service told me that it would cost me $300 diagnosis fee (UNLESS it is determined that I do in fact have subframe rot, then it would be waived). Since i'm unsure if this is my actual issue, I'm hesitant to pay the $300 just to be told it's not the subframe. Is the subframe perforations something I can see on my own, take pictures of and be sure this is my issue before I bring the car in? It would be great if there was a bunch of example photos so I can avoid this fee.

deadlyvt

Yeah go under the rear of the car subframe is attached to the differential check for rot/weld failure