Originally Posted by paul huyck
I'm a retired mechanic after 45 years in the business. I would agree that the brakes need to be bled to correct the problem, but that is a simple fix and I'm sure that Mercedes would have done that long ago instead of having so many complaints about the spongy brakes. I have read all of the supposed fixes that didn't work and believe that is an inherent problem with the vehicle, such as soft brake pad materiel.
I will certainly defer to your years of experience, however if one calls MB corporate about something that calls for bleeding air out of the brake lines, I wouldn't expect much help there. Help for that would be found at the MB dealer service department, a brake shop or a trusty service station.
I would love to see and touch a soft brake pad. Not sure how it wouldn't be ripped to shreds by truck wheels turning at 65 mph when the brakes are applied. All the ones I have ever handled were hard. But then hardness has its levels apparently.
If one steps on the brake pedal and it travels down 3" before engaging (which I believe some are complaining about), I would say that is compressing air in the line not brake fluid and the force hasn't even gotten to the brake pad yet. But I can't rule out some other issue like a master cylinder problem too. I'm just saying most commonly one would find air in the lines and it sounds like you agree on that point.
Air could be getting in the line due to a leak in the system letting air in or letting the fluid level get too low. A leak can be verified or ruled out by a mechanic when doubt the bleeding. Also pavement spotting or visually observed leaks could be a symptom.
Many thanks - appreciate hearing from someone with long experience in the field!