I have a 2006 Mercedes-Benz C230. For the past few weeks I’ve been experiencing screeching sounds when driving. And sometimes it almost sounds like something is dragging underneath the car. It gets worse when I am slowing down. Could it be my brakes?
The only way to determine what’s causing the noise is, bring the vehicle to a shop and have it inspected.
If it screeches only when you put the brakes on then it could be the brakes, but someone needs to take a look at it. I hauled some branches to the dump and needed to make a long trip the next day. I had a noise under the car and when I crawled under and looked, I had picked up a branch that I had been dragging around. Pulled the branch out and all was well. So who knows?
Good advice above to go a shop for this problem. You could do a couple of experiments then tell the shop what you have discovered. For example, when this happens, does it stop when you lift your foot off the accelerator? Does it stop when you give it more gas? Does it stop when you shift to neutral and coast? Does it seem to happen only at certain speed ranges or certain gears? How does applying the brakes affect it?
One common reason for a screeching noise when applying brakes is the brake pad wear indicator. If that’s the cause, you need a set of new brake pads. The wear indicator is built into the brake system and warns the driver with a screeching noise when the pads reach their wear limit.