You should read this if you own an ML, GL, or R-Class.
Mercedes-Benz is facing one of the largest recalls in its history, and it all started with one car. The cars affected by the recall are the Mercedes-Benz ML, GL, and R-Class, and only models produced between 2006 to 2012.
In July 2021 a customer complained about a reduction in brake force support. While studying the car to find the problem, Mercedes engineers noted corrosion on the brake booster's housing. Instead of fixing just this one car, Mercedes launched a global investigation into models that used the same brake booster. This investigation was conducted with the help of Continental Tire The Americas, which supplies brake boosters to Mercedes-Benz.
Another case of a corroded brake booster was identified in March 2022, and now Mercedes is recalling more than 292,000 vehicles made between 2006 and 2012. Thankfully for Merc, it's not as big as the 2017 fire recall.
It's a severe problem, and Mercedes is asking owners not to drive their cars because the brakes could fail. Mercedes will offer a free towing service to the nearest dealership. If the problem can't be fixed on the same day, dealers will help owners find loaner vehicles.
It's worth noting that there have been no crashes or injuries reported due to this defect.
The National Highway Traffic Safety Administration (NHTSA) published the recall details earlier this week.
The brake booster is covered with a rubber sleeve that may leak water, leading to corrosion. The major corrosion point seems to be the joint area of the housing. If the part is exposed to water for long enough, the brake booster could leak, which results in a loss of brake force.
In severe cases, the brake booster can suffer irreparable damage. These cases are extremely rare, however. Mercedes also states that it does not affect the parking brake.
The recall is not limited to a specific trim. All ML, GL, and R-Class models are part of the recall. If you are an owner, you will notice a difference in the brake pedal feel, and you might notice hissing noises.
The rubber sleeve will be removed at the dealer, and the brake booster will be inspected. If there is little to no corrosion, the vehicle will be returned to the owner. If there is corrosion, Mercedes will test the car. Once it passes the said test, owners get it back, and they may continue to drive it for 24 months before returning it. If it doesn't pass the test, Mercedes will replace the brake booster.
Considering the high replacement price of a brake booster, Mercedes likely wants to avoid fitting a new unit to each of the nearly 300,000 vehicles.