Ah, I never uploaded my video. Suppose I will do so!

 

Just discovered the same problem on my 2009 C300 4matic with 65,000 miles.
My mechanic, who is a friend of mine showed me the lines when it was up on the lift and they are terrible. They are leaking in one place and close to corroding through in several other places.
I’m in Chicago suburbs and he said they are doing a tremendous number of these now.
So many that he said he’s surprised there hasn’t been a class action lawsuit filed.
Have many of you been having this problem?

 

I put a film on my lines and bolts underneath the car. I need to take all the panels off and check things out and do an undercoating.

 

Sorry to rehash a year-old thread, but I'm at the dealership now and received the same exact news. My brake fluid red warning flashed on my car last week, but had to drive it a few times until I could get my annual service scheduled. Anyway, 75k on my 2009 C300 in Chicago suburbs. I had told the service rep that I don't drive the car a lot (few hundred miles a month at most). He told me the brake line replacement would be likely be thousands of dollars. He actually showed me the issue, pulled down a flap on the driver-side of the car where the brake line runs, and its very rusted and wet (from the fluid leaking). For now, he changed my Service B to a Service A and will just top off the brake fluid rather than flush and replace, since it will just continue to leak.

May I ask what you ended up doing, and if replaced, around how much the cost was? I'm not sure how I want to proceed now because I was planning to continue driving this car for a while.

 

you need to replace it, otherwise your car will be undriveable without brakes

 

I’m having the exact same issue with my 2009 GL 450. There is no rust or corrosion anywhere else on the car except for the brake lines. I live in Georgia and believe the car has been here It’s entire life so don’t believe it’s ever been driven on heavily salted roads. For me the leak occurred on the two rear lines underneath the rear drivers side door where the lines are secured with a rubber bracket. I noticed that my brakes started fading, and if I sat at a red light, the pedal would slowly go to the floor and then the vehicle would start moving, I would have to let off the brakes and re-pump them to stop again for a few seconds. Just took off the under panels and found that the lines are extremely rusted. Don’t understand how the hell Mercedes could use such an inferior product for their brake lines. My vehicle has a recall for corrosion at the brake booster, but nothing at all for the brake lines. Sounds like this is actually quite a common problem and should be a recall item.