GLK SQUEAKY BRAKES :-(
I've had mine for 2 years and not a peep from the brakes.
BTW C300 and C350 have different rotors and pads. I think GLK's rotors are similar to C350 not sure if they are identical.

After a few road tests and on different appointments, the darn brakes would not squeak with the MB technican.
I tried again a few weeks ago with the SA and no go. Finally, I stated while coming back from a test drive to the service garage, I need to try one more time...and lo behold, it squeaked!
The SA did mention something about the water / rain / moisture having an effect on the squeaking?

My GLK went in for service today and getting a few other touch ups like the rear wiper, side mirror motor, and gas door...
As NYCGLK says... tell them to cut the crap
...this is an MB not a domestic. 
It happened at low speed and not every time. My SA told me that Mercedes Benz recommends high speed brake application to take the glaze off the pads and reduce the brake noise. I talked to a friend who has an E class (his third Mercedes) and he has the same problem and says he he would drive with his foot on the brake for a short distance and the noise would go away. Another friend has an old merc and installed his own brakes, He had the same problem and put some anti-squeak grease on the piston? that holds the brake pad and the noise went away.
Worn Pads
A brake pad is comprised of steel backing with friction material attached to it. Application of the brakes produces hydraulic pressure that causes the brake pads (via brake calipers) to clamp down on the rotors (discs) creating friction as the car is in motion. It is the friction of the pads against the rotors that slows and stops the vehicle. When the friction material on the pads wears down enough, it is time to replace the pads. Some pads are equipped with a wear indicator, which is a small spring steel clip. When a pad is worn, this clip makes contact with the rotor and generates a high-pitched squeal, telling you that it is time to service the brakes. Our Mercedes has an electronic wear indicator but only on one side. When the pad is almost gone, a warning will light on the dash.
Glazed Pads and Rotors
Brake squeal can also occur when the brake caliper sticks and the brake pad stays applied to the rotor. This happens mostly with carbon based pads that create plenty of black corrosive dust. When this happens the pad can either be in constant contact with the rotor, producing excessive friction and thus heat or partial contact with the rotor causing a resonating squeal. Overheated pads usually harden and then crystallize crating a "glazing" on the rotors and pads as well. The squealing sound is a result of these super hardened surfaces coming in contact with one another. Remember, it is the friction created by the brake pad against the rotor that stops a vehicle. When crystallization of pad and rotor occurs, there is much less friction, like finger nails on a school blackboard, the two slick surfaces create a tone. This results in diminished braking power and annoying squealing brakes. At this point the pads should be replaced and the rotors either resurfaced or replaced.
Broken Anti Rattle Clips
The brake pad is loosely held in place on the caliper by pad retainers, pins, rails, guides or stays. An additional part called an anti rattle clip is used to secure the pad so that it will not vibrate or rattle when the brake is applied. If anti rattle clips are worn or broken, pad vibration will cause squealing. In this case, the clips should also be replaced, especially when the pads are routinely replaced.
Lack of Pad Insulation or Insulation Shims
When a car comes from the factory, insulation anti-squeal shims are placed against the steel backing of the pad to insulate it from the brake caliper. This is necessary to prevent brake squeal. These shims that have a smooth teflon surface eventually wear out or they are sometimes wrongly discarded when a brake job is performed. When the pads are replaced, either new shims should be installed or orange Brake-Quiet silicone insulation gel must be applied to that inner surface of the pad to prevent squeal. If you had your brakes replaced recently by the dealer or anyone else and they're squealing, it's a good bet the shop failed to install new shims or Brake-Quiet.
Incorrect Rotor Surface Cut or No Surface Cut at All
When a brake job is performed, the rotors must be resurfaced to remove any glazing and return the surface to a "true" flat disc shape. First the rotor is machined to remove grooves and/or imperfection on the rotor surface. Once the rotor face is "true," a slow, non-directional finish is applied to the rotor face to ensure proper break-in of the pads. This process also insures that the pads don't ride up on the face of the rotor when braking. Riding up of the pads can cause a clicking sound, the breaking of anti rattle clips, or caliper pin wear. If the rotor is found to be too thin according to state inspection rules, it is discarded and replaced with new ones, and should be done in pairs, either both front or both rear.
It is also important to note that if your pads were replaced without resurfacing the rotors, then squealing and pedal pulsation will probably occur.
Last edited by MBRedux; Dec 6, 2011 at 01:36 PM.
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I usually do my own brakes and do nothing fancy but I do put some red CRC Disk Brake Quiet goop on the back of the pads where the clips are on the end.
I replace with Centric 125.35080 Hi Carbon disks and Centric 105.14060 ceramic pads for a 2010 GLK350AWD. These are the same front disks used on an E550. I like Akebono pads, but thought I might try the matched set of Centric's. The Centric's also have a coated center so they don't show any rust. Cost with shipping is $207 . If the dealer didn't put the front wheels on with a torqued out air wrench, should take about 1-1/2 hours. Dealer wanted $650.
Job completed using Centric's. A little hard to get the disks off but a big hammer works. Total job 1-1/2 hours including cleanup. After 14 ,000 miles still no squeak or dust. Will do the rears the same way when they need it.
This type of braking application will lead to a nice film developing on the rotors.
Whenever her GLK becomes squeaky I take it out onto the highway and do a few hard stops from 150-160 km/h -- always solves it.
I have my C63 on storage status right now with same parking situation. I noticed when I moved it a few feet to adjust weight on the tires I could see on the rotors where the parking brake had been at previously.
This has lead me to the theory, that the squeaking is caused by residual brake dust after have the parking brake on. Unfortunately there aren't any areas flat enough in the drive way to park without have the parking brake on.
Will do a couple hard brakes and see if it goes away.
Took it into the dealership and was told the same thing about glazing. Did a few brake stomps to alleviate it. Squealing still happens from time to time, but it seems to be at its worst during very cold weather, and almost non-existent during above-freezing weather. When it's warm out, there is no squealing at all.
So is it really a glazing issue (given its appearance only during damp/cold) or should I take it in and demand they replace pads and/or rotors? (my GLK has about 9,000 km on it by now.)
I have had a third-party mechanic do everything - reshaped the rotors after they still squealed after the first replacement, replace both front and rear brake pads/rotors, tried different brands (I think they used the MB ones first and they still squealed - then they put on Akebono rear brake pads and Zimmermann rear brake rotors), and they still are squeaky sometimes.
When I brought it into a MB dealership the service advisor said they could have a look but the squeaking would generally come back so as long as I was certain that the brakes were good, I decided to not spend the money to have them look at it.
Brake dust on the front wheels is a big problem too, I am not sure if this contributes to the squealing problem or not.
Also, the way you brake might have an effect. Through the MB Driving Academy I was told to apply harder, increasing braking to see if this helps, but I am the type of driver who leaves plenty of distance in front of me and comes to a gradual stop. Hard to change habits!
BUT: My friend with a BMW X1 has a similar issue, so it isn't just MB.
Last edited by Awesys; Apr 6, 2014 at 04:24 PM.
I'm not saying the issue isn't perhaps more complicated in some situations, but this is one of the most common things on any vehicle.
I will certainly try the hard braking and that may solve it!
Out to a country road, took it up to 100 three times and did full ABS-engaged stops to a full stop in quick succession. Never heard a peep from them since.


