Squeaky rear brakes

[WDJ]

My 2021 MP has developed a high pitched squeal from the rear brakes (like a whistling sound). MB replaced the rear shoes and hand brake cable to fix it. It didn't work. Has anyone experienced this and what was the resolution?

 

[Roy C]

Yes, I have and there is also a thread on here about it if you search.

For me the squealing was often but not always present but, when it was, the squealing went away when I touched the brakes. Is this what you have? I took it to my MB dealer twice (£85 investigation fee each time) and they said they couldn’t hear it but thought it was corrosion. They said they could replace the discs but there was no guarantee it would work. Faced with this lack of confidence I took it to an independent specialist and they diagnosed the same but were confident they could fix it and said if it didn’t work they’d keep trying at no extra cost. They replaced the corroded rear discs (corrosion had created a lip) and cleaned the corroded calipers so they fully released so the pads weren’t touching the lip on the discs and causing the squealing. Cost about £400 if I recall correctly but worth it because the squeal was driving me nuts.

 

[WDJ]

Thank you Roy. Sometimes the squealing stops when I touch the brakes but not always My van is back at the dealership this week.

 

[Rm15427]

I had rear wheel squealing develop on my 2022 MP after a year of use. Initially started on steep inclines/descents in the Alps. MB dealer could not find anything. Then problem became more persistent. Took back to MB, still no idea. Took to a different MB dealership, same answer. Eventually took it to an independent brake specialist. They found calipers were ok, but pads seized , causing them to stick and creating a groove on the discs. Replaced both real discs and pads . Cost £465 ( out of warranty by this time ) Problem solved
Don’t know why the MB dealerships couldn’t find this out

 

[Kuba]

I had this problem for 12 months and the official MB deal could not find what's wrong. They polished the disks and replaced the pads -- no improvement. The noise was more pronounced by the dry weather. In wet weather is was quiet. At the end, they figured out rust with the *handbrake* system (cable). They replaced some parts and now the noise is gone. Maybe this will help in your case, too.

 

[Dutchyankee]

After a long journey to Southern Italy and back to NL, I noticed a strange sound that I thought was from the rear brakes dust shield as the brake pads and disks were recently replaced. It was louder when driving in reverse then forward.Turns out it was the bearings in the drive axle from the transmission to the rear differential. Needed to replace the entire assembly. It’s not a maintenance thing and with nearly 300KM, I guess it was time.
This year, similar trip a terrible metal on metal sound in the rear brakes. It turns out the inside calipers were stuck and wore the recently replaced disk and pads after 10KM.
I always have a pre vacation check done before we take long trips but I guess it’s just bad luck. The alternator died just as we reached Etna which was erupting. All turned out ok and we were able to witness this spectacular natural event.

 

[MrDrew]

This seem to be a classic MB W447 issue. A friend has a brand new one, less than a year old for his business. HIs already stared making the squeal. I think almost all of them do this.

I needed to replace my brakes anyway, so I installed ceramic pads, and coated discs. No problems yet. since last May. I did the work myself so it didn't cost me Mercedes repair prices.

 

[j200george]

I had this, majorly embarrassing rocking into a campsite driving what sounds like a coco the clown car. Changed brakes and discs (they were needed) and hasn’t happened again. I’m sure it’ll come back though.

 

[Steve B]

I had a squeaking sound from the brakes last year, stuck calliper, new pads and its been fine.

 

[Greens_Peace]

I had a very similar problem on my Mercedes based Hymer. It would seem to be a common problem, the suggestion was is was down to lack of use, which in my case was true, a lot of sitting around either on my drive or on campsites. It got so bad at one point that I call the Mercedes road side emergency number and the Mercedes dealership at Aberdeen sent a chap out who fixed it on the road side, annoying only one side as I didn't mention in my phone call that both sides were affected. You could have cooked breakfast on the hub it had got so hot. Basically it is the auto adjust of the callipers, it gets very dry and thereby corroded so does not return to a position where they are not binding on the brakes, this through lack of use. Once taken apart and 'greased' so that they are free to move easily back and forth the problem is cured. It was, and once I had my local garage do the other side all was well.