Grinding Noise From Front Left
MBWorld Fanatic!
Joined: Jul 2012
Posts: 1,369
Likes: 319
From: WI
GLK 250
Note that it's not the caliper sliding pins I'd be worried about, rather the caliper itself. The seals around the pistons could have gotten hard/torn/damaged in some way which lets in moisture and corrosion can form. This leads to the piston(s) not fully retracting when you lift off the brake pedal. As a result, the caliper pistons still hold enough pressure on the brake pads, which generates extra heat and brake dust. This can lead to warped rotors among other things.
Point is: have you confirmed with a thermometer that both front brake setups are running at the same temps? Do you have more brake dust on one wheel vs the other?
BTW: that caliper looks like a refurb to me. Maybe it's been replaced once?
Point is: have you confirmed with a thermometer that both front brake setups are running at the same temps? Do you have more brake dust on one wheel vs the other?
BTW: that caliper looks like a refurb to me. Maybe it's been replaced once?
Thread Starter
Junior Member
Joined: Mar 2020
Posts: 22
Likes: 1
From: Dubai
2014 GLK250
Couldn’t take it to the mechanic due to covid-19 restrictions.. the issue has not been resolved still there. I will definitely share the result if i can find a fix.. otherwise I’ll sell my GLK..
Thread Starter
Junior Member
Joined: Mar 2020
Posts: 22
Likes: 1
From: Dubai
2014 GLK250
I checked the slider pins myself, no damage around the rubber seals, sliding smoothly.. i did take a video but can not upload in here.. regarding the caliper history i have no idea, but it’s only 50k mileage so I don’t think so.. also I don’t have the thermometer so didn’t check the temperature.. as per 3 mechanics the breaking system is okay. I will take it MB specialist when everything settles down.. thanks for support, highly appreciated.
MBWorld Fanatic!
Joined: Sep 2015
Posts: 2,585
Likes: 343
2013 glk 350
How could anyone state it’s not the caliper since you didn’t have it taken it apart and opened up for inspection?
You have no idea on the internal conditions or possible corrosion that could cause sticking.
Did you even jack it up yourself and let it sit overnight then hand turn the wheel?
I had wheel brake cilinders fail from visible pitting, corrosion and rust debris. Moisture gets inside.
Find the bad wheel , replace the wheel cilinders and ALL fluid.
You have no idea on the internal conditions or possible corrosion that could cause sticking.
Did you even jack it up yourself and let it sit overnight then hand turn the wheel?
I had wheel brake cilinders fail from visible pitting, corrosion and rust debris. Moisture gets inside.
Find the bad wheel , replace the wheel cilinders and ALL fluid.
Thread Starter
Junior Member
Joined: Mar 2020
Posts: 22
Likes: 1
From: Dubai
2014 GLK250
Thanks for all the replys.
This was the only check up for the caliper so far. In Dubai mechanics are not good at repairing they are so used to replace therefore hard to find someone who understands this kinda stuff.. Me personally even learned in here how the caliper works so I don’t know how to deconstruct.. However since everybody in here betting on the caliper, i will try to find a brake expert and get it checked.. I don’t have a thermometer when explained it to my fellow mechanics in here they didn’t even understand what I am talkin about unfortunately. Believe it or not, i want to get this fixed so badly because i really enjoy driving my MB..
This was the only check up for the caliper so far. In Dubai mechanics are not good at repairing they are so used to replace therefore hard to find someone who understands this kinda stuff.. Me personally even learned in here how the caliper works so I don’t know how to deconstruct.. However since everybody in here betting on the caliper, i will try to find a brake expert and get it checked.. I don’t have a thermometer when explained it to my fellow mechanics in here they didn’t even understand what I am talkin about unfortunately. Believe it or not, i want to get this fixed so badly because i really enjoy driving my MB..
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MBWorld Fanatic!
Joined: Jan 2009
Posts: 2,780
Likes: 115
From: Northern NJ
GLK 350 / Porsche 993
Ok let's be logical...friction noise come from something moving/rotating....so rotor, wheel, axle on something stationary....pad, dust shield....I'm running out of ideas.
If it's rotor/pad making the noise you should have the noise regardless of suspension travel, too bad you can't leave it on the lift for a while. My first guess you just had something stuck between the rotor and dust shield (the metal round cover behind the rotor). The shield can also rust and paint peels off. But given only 50k miles in UAE, there seems to be zero rust. Your calipers look fantastic and I highly doubt you have sticky piston in the caliper.
There can be just natural pad to rotor rubbing intially.
Can you try one thing since you are on a lock down...after the car has been sitting for while, lift the front rubbing wheel (with the jack in the kit) and rotate the wheel by hand. You might need to put the car into N given AWD. See if you get the noise. If you do take the wheel off and rotate the rotor, you should be able to see where noise is coming from. Make a video of the noise.
If it's rotor/pad making the noise you should have the noise regardless of suspension travel, too bad you can't leave it on the lift for a while. My first guess you just had something stuck between the rotor and dust shield (the metal round cover behind the rotor). The shield can also rust and paint peels off. But given only 50k miles in UAE, there seems to be zero rust. Your calipers look fantastic and I highly doubt you have sticky piston in the caliper.
There can be just natural pad to rotor rubbing intially.
Can you try one thing since you are on a lock down...after the car has been sitting for while, lift the front rubbing wheel (with the jack in the kit) and rotate the wheel by hand. You might need to put the car into N given AWD. See if you get the noise. If you do take the wheel off and rotate the rotor, you should be able to see where noise is coming from. Make a video of the noise.
Thread Starter
Junior Member
Joined: Mar 2020
Posts: 22
Likes: 1
From: Dubai
2014 GLK250
Thanks for the reply, appreciated.
Honestly i have checked it before.
When the car was on the lift, i rotated the wheel manually to see if there is a friction or a noise coming from it and there was nothing.. i tried backwards as well nothing no noise Or friction feeling at all.. also i tried with the wheel off only rotor was very hard to rotate the rotor tho..
Bonus: here is the video of the caliper sliders, felt very smooth..
Honestly i have checked it before.
When the car was on the lift, i rotated the wheel manually to see if there is a friction or a noise coming from it and there was nothing.. i tried backwards as well nothing no noise Or friction feeling at all.. also i tried with the wheel off only rotor was very hard to rotate the rotor tho..
Bonus: here is the video of the caliper sliders, felt very smooth..
MBWorld Fanatic!
Joined: Jan 2009
Posts: 2,780
Likes: 115
From: Northern NJ
GLK 350 / Porsche 993
^ yes I read that part about lift, but I guess the car didn't sit on the lift overnight.
Yea pins look good, but what gets sticky is the piston in the calipers. But you (or your mechanic) would know when doing brake change as it would be very difficult to get the piston back in.
You sure it's rubbing noise?
I have Lexus LX570, and when I got it I could swear I had bad wheel bearing (rubbing noise), only to realize the wind noise from the mirror with open window at slower speed was creating similar noise
))
Yea pins look good, but what gets sticky is the piston in the calipers. But you (or your mechanic) would know when doing brake change as it would be very difficult to get the piston back in.
You sure it's rubbing noise?
I have Lexus LX570, and when I got it I could swear I had bad wheel bearing (rubbing noise), only to realize the wind noise from the mirror with open window at slower speed was creating similar noise
))
Thread Starter
Junior Member
Joined: Mar 2020
Posts: 22
Likes: 1
From: Dubai
2014 GLK250
LOOL
I am pretty sure that it’s not the wind
Actually in here it’s already so hard to be around the car when mechanics are working on it, strictly regulated, I am pushing the limits to do so therefore i don’t think it’s possible to leave it on the lift overnight and try the day after.. Only thing that i am thinking is taking it to the Mb specialist garage and leave it there let’s see what they will come up with...
I am pretty sure that it’s not the wind
Actually in here it’s already so hard to be around the car when mechanics are working on it, strictly regulated, I am pushing the limits to do so therefore i don’t think it’s possible to leave it on the lift overnight and try the day after.. Only thing that i am thinking is taking it to the Mb specialist garage and leave it there let’s see what they will come up with...
MBWorld Fanatic!
Joined: Jan 2009
Posts: 2,780
Likes: 115
From: Northern NJ
GLK 350 / Porsche 993
Actually in here it’s already so hard to be around the car when mechanics are working on it, strictly regulated, I am pushing the limits to do so therefore i don’t think it’s possible to leave it on the lift overnight and try the day after.. Only thing that i am thinking is taking it to the Mb specialist garage and leave it there let’s see what they will come up with...
MBWorld Fanatic!
Joined: Jan 2009
Posts: 2,780
Likes: 115
From: Northern NJ
GLK 350 / Porsche 993
I do most things myself or with a couple of friends. Simple things like brakes or oil changes, can be done in a parking garage of an apartment building. It's faster and more convenient than schlepping to a dealer and waiting to get your car back or come back to pick it up.
I have 2 SUVs, and 2 Porsches so I'd be broke if I took them to dealers.
Newbie
Joined: Nov 2021
Posts: 1
Likes: 0
GL350
I have the same issue GL350
Hi all, I talked to the official MB dealer garage today.
I explained the situation and the mechanic was like , I am pretty sure it's a suspension issue.
His thesis is, when you park over the night, suspension goes down and when you run the engine in the morning suspension goes up that's why first couple of minutes, I have this grinding noise and it fades away..
This sounds logical to me, I will get my suspension checked.. what do you guys think ?
Any thoughts ?
I explained the situation and the mechanic was like , I am pretty sure it's a suspension issue.
His thesis is, when you park over the night, suspension goes down and when you run the engine in the morning suspension goes up that's why first couple of minutes, I have this grinding noise and it fades away..
This sounds logical to me, I will get my suspension checked.. what do you guys think ?
Any thoughts ?
I'm reading through your post and it seems like these guys were so far off on the rotor issue. Mine comes from the front passenger and I'm almost convinced it the air matic system. I can hear the noise at any random time moving or not moving but after the noise ended there is always the air puff sound that Mercedes makes. In my experience this kind of noise happens in machines when fluid is low or when there is air escaping from somewhere, when something is loose or finally when something is worn out. I would advise you to have the air matic checked, There has to be some kind of compressor feeding air to it and it is possible it has gone bad some how.
Please let us know the final results!!!
