Every time it rains, the next day my brakes lock up. I’m sure it’s brake dust, pads, etc. from being wet then drying in my garage overnight. Today it was so bad, I had to put the pedal half way down to get it to move in reverse. It bangs so hard, it scares the hell out of you when the brakes finally release. It’s usually fine after that but today it clicked so loud after putting it in drive with every tire rotation. Has anyone experienced this? Is there anyway to prevent it? Not only is it scary, it’s embarrassing. The whole neighborhood can hear it.

 

Happened in my S and GT after rain or a car wash

 

Very common issue on many cars. There's metal in the brake dust and the pads will seize to the rotors if the brakes are wet. To avoid it, dry the brakes before parking. Not really an option when it's raining, though, but after a car wash go for a quick drive and use the brakes to dry them. If you must park with wet brakes, make sure you manually release the parking brake. It's the rear pads that generally seize, because of the parking brake, which automatically engages when parking.

 

Thank you! I’ll give this a try next time. I hate that it only happens to this car…

 

It has become more of an issue, because many newer cars automatically apply the parking brake now for safety reasons. Didn't used to be like that.

 

I have the same issue. I have been at the east coast shore all summer where it is very humid. Most mornings I have the same issue after the car sits all night, wet or dry the night before. I spoke to the dealer and he said it’s “Normal” for this car. Annoying, nonetheless.

 

Lord, half throttle to get moving is a huge amount. Could you walk around your car and snap a picture of each disk to look at current aspect. The disks will tell us more...

Is this from wet rust gluing pads to rotor or from the EPB auto parking brakes not fully releasing

 

I’d wager “ half throttle” was an exaggeration.😱

 

This is the sound they make. I was told again this morning by my service writer that the lead tech said it was normal. Yes, you have to put the gas pedal down at least half way to make them unlock. I have to double check that I’m in drive so I don’t drive into my house. How can this be normal? This is my 7th S-class and have never experienced this before.

 

Yep, that's the sound of seized brake pads. As said, completely normal. Part of the problem is the automatic engagement of the parking brake these days as I mentioned above already. So the wet brakes make contact and start to rust. To avoid it, manually release the parking brake after shutting the car off and opening the door, so the car won't sit with wet brakes and the parking brake engaged.

 

Sorry I can't read proprietary MOV files.
Pls upload an MP4 or standard encoding.


Be proactive by searching for known issues in published TSB. Good chance you can find the exact procedure to repair factory issue. This will make your issue harder to brush off


Service desk stories change...
-- now it is "nothing wrong!"-- soon it will be "wear and tear is not covered!"

 

Great idea. Thank you

 

Great suggestion!

OP, try this, just before you press the ignition button to turn off the engine try pulling on the parking brake switch (Edit: forgot to mention, make sure to keep pulling on it while you turn off the engine), it should stop the parking brake from engaging when you turn off your vehicle. You need to do it every time you shut off the vehicle. At least, this is true for most MB models from what I heard. I am not sure if this is still applicable for the W223, hopefully it does, try it and let us know.

 

Another possible option is to ride the break just before coming to park in a wet condition so that the hot rotor boils off the water (boil=heat induced evaporation)... Of course this means unnecessary brake pad and rotor wear as a remedy for a problem that really should we not be experiencing in the first place...

Unsure if this will work....

 

Also, pretty sure all modern MBs have automatic brake wiping tied to the rain sensor. If you have the windshield wipers on auto and it detects rain, the brakes should automatically slightly apply the pads periodically to wipe the water off the rotors and ensure good stopping power in the wet. This should also minimize the seizing of the pads to the rotors after parking the car. It doesn't rain much here in NorCal, but I've only ever had this issue on any car that automatically applies the parking brake if I parked the car right after washing it and not taking it for a drive to dry the brakes. Never had this issue after it rained.

 

Applying brakes after a car wash helps although proper drying needs quite some braking force (and time).

I just don't get your comment on the problem not supposed to occur in the first place. This was less of an issue when we still had brake pads with asbestos (and discs accordingly). Today this happens to all cars, often even if the parking brake has not been applied if just the discs are left completely wet before parking.

 

To me, half throttle is excessive. I'm in Seattle where it rains a lot of during any part of the year not called summer. The car has been put away wet countless times with nothing more than a light pop that required little extra throttle to overcome.

Are we saying half throttle is normal, expected, on a day-to-day basis? This doesn't jibe with what I've experienced with this car.

 

imho...It shouldn't happen because the engineer should understand the issue and have a solution whereas the car pulls the pad Off the rotor..... I drove a manual shift cars for many years and had to set the park break in the rain all the time and when I disengaged the park brake the car took off without issue....100%.... This solution can be engineered....

 

Ages ago Mercedes used to dry the rotors during rain to maintain maximum brake performance, as part of the Adaptive Brake system. Assume this is still in place?

"When driving on wet road surfaces, this technology is able to routinely apply brief braking impulses to clear moisture and water droplets from the brake discs. These tiny impulses are unable to be noticed by the driver."

 

yeah this happened to me couple times but I didn’t heard any sound. My brakes just got locked I pressed the gas little bit and the car launched quickly. But no sound. It was just kinda weird

 

Well, physics is physics. Back in the days, brake pads contained asbestos and we all know what the problem with that is. Nowadays, most brake pads are semi metallic, because they perform well in most conditions, but they contain iron and as we know iron corrodes. The rotors are also made of iron so the rotors and brake dust quickly bond as the iron starts to corrode under favorable conditions. You can use ceramic pads. They don't contain metal, but ceramic pads don't perform well when cold and don't offer the initial bite that semi metallic pads do. Everything on a car is a compromise to handle different environments etc. and every compromise comes with downsides. There are more upsides to semi metallic brake pads than there are downsides and the downsides are manageable if you understand what causes them such as parking with wet brakes.

 

This is crazy...I've never experienced such a thing in any car I've ever had, including my S560...

 

The experience will vary depending on your climate and other environmental factors. We have salt in the air from the ocean here for example. Other region have salt on the road in the winter. Different temperatures and different humidity levels all make a difference, but this happens on all kinds of cars in the right environment. For example when I went test driving AMGs most of the cars in their lot had seized brakes like that. The sales person was very aware of it and carefully broke them loose. It's just like rusty rotors. In some climates you see many cars with rusty rotors, in others like here you don't.

 

BMW performance brakes are notorious for that. Trying to move the car after a wash the previous day makes it sound like you are braking an axle. Complete non-issue to me

 

I experience this brake noise all the time as my V223 is washed almost daily. If I do not drive the car for a few days, there is always a brake noise.
Of all these years, I can recount only a handful of times when I needed to step on the gas pedal to break loose the 'baking bond'.
Most usually, I just swift from 'P' to 'D' and the forward rolling force will be enough to break the bond, without the need to apply throttle at all.

Sometimes the noise can be loud and get scary...lol