Scratching sound from brakes

[VenomX]

Hi guys.
Have a C240 2002 with about 39K on the clock.

When turning left I hear a scratching sort of noise, coming from the front left, it subsides immediately if I apply the brakes ( even lightly ) Can only hear it when windows are down
The discs have never been replaced in 23 years but the pads have about 10 months ago ( brembos )

Any ideas ? I am thinking the discs are old and need to be replaced
I will get the car in the air when I get a chance and see if I can see anything off such as uneven pad wear or dry sliders
Tracking needs to be done as I have done a lot of suspension work on the car including control arms/track rod end/struts

Thanks

 

[W1ghty]

Hi guys.
Have a C240 2002 with about 39K on the clock.

When turning left I hear a scratching sort of noise, coming from the front left, it subsides immediately if I apply the brakes ( even lightly ) Can only hear it when windows are down
The discs have never been replaced in 23 years but the pads have about 10 months ago ( brembos )

Any ideas ? I am thinking the discs are old and need to be replaced
I will get the car in the air when I get a chance and see if I can see anything off such as uneven pad wear or dry sliders
Tracking needs to be done as I have done a lot of suspension work on the car including control arms/track rod end/struts

Thanks

Might well be something stuck in the pads ?
The C class platform does have an issue with the foot brake cable running front to back that breaks a clip in the underneath centre of the car and allows the cable to contact the prop shaft , so if it’s not the brakes bear this in mind .

 

[Tonye]

Could be just a chunk of grit stuck behind the back plate, happened to a mate of mine, got so hot it welded itself to the plate.

 

[W1ghty]

S

Thread 'I've got a very odd (rotational) noise coming from my CLKs gearbox area!'

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Hi All,

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In the last couple of weeks, the car has developed a weird rotational noise. The car shifts perfect in C or S, but under heavy load, there is just this weird sound. It got ever so slightly louder when i removed the shifter cover. Could be either the propshaft or (hopefully not) from inside the 'box. The noise does get 'harder' when i went around a mini roundabout at speed.

I don't have much access under the car, so managed to get the covers off and have a look. The flex...

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[W1ghty]

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Thread 'CLK 2009: rubbing/scrapping sound prop shaft'

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Hello, I have recently purchased a used CLK 200 Kompressor Cabriolet (2009). It has around 69k miles. A road speed related scrapping/rubbing noise (bit like a wheel bearing) has started emanating from, I believe, the front of the transmission tunnel. I’ve read about park brake cable clips breaking leading to the cable rubbing on the prop and from other peoples descriptions it sounds identical to my noise ,however, one thing that is throwing me is it gets louder when everything warms up after a few miles and then has a consistent noise that varies with road speed. Obviously I’m trying to...

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[Trickythemerc]

The turning left confirms that it will be the park brake cable hitting the prop shaft. I have a clip available for the price of a pint.

 

[VenomX]

Thanks guys I will have a look when I get a chance .
If it subsides when I apply the brake lightly, could it still indicate the prop ? I have read a few threads regarding that and people tend to say the noise comes from the centre of the car, whereas when I hear it, it is definitely only the front passenger side with the window down.

What I will do to rule out the brakes I will jack the car up, and spin the wheels at the front to hear if the sound is present when the prop isn't spinning

 

[VenomX]

Right.
I have checked the propshaft/handbrake cable situation. Behind the transmission sump I can see three blue clips, all holding the handbrake cable in place securely, so that looks fine.
I have replaced pads and discs, noise still there.

Upon inspection, there is a tiny bit of play 12 and 6 when rocking the wheel, but not in any other directions ( I think it is the other control arm that I have not replaced yet causing this )
Not sure if it could be bearing related? It stops " scratching " when applying the brake. And does not sound like a growling noise that a bad bearing usually would.

Any suggestions welcome, thanks.

BTW the tracking will be out by a fair bit due to all the work I've done on it, getting round to that this week ( car drives straight and does not pull )

 

[slade1]

Small stones/grit in brake calliper? Also wheel bearings need adjustment.

 

[VenomX]

With the car in the air if I spin the wheel, no noise. On the ground, it does make a scratch when driving. The only thing that changes then is how the wheel sits.
Could potentially be if the tracking is out after all the suspension work done on the car, the wheel is not correctly toe in/out , and the pads are therefore rubbing against the disc ?

 

[Petrol Pete]

23 years ? how are the backplates/dust shields ?? on my 19 year old C class they are WELL crusty and OEM . ...another job on the list

Just in case you want to go with the handbrake cable theory this is what you are looking for. By the way when my handbrake cable did this the noise sounded like it was coming from the torque converter area forward of the gear selector , very odd noises.

At that age the blue plastic clip could have rotted and let go. As in my photo. Do not discount this theory , it's a pretty easy one to check for yourself.

 

[Pontoneer]

Hi guys.
Have a C240 2002 with about 39K on the clock.

When turning left I hear a scratching sort of noise, coming from the front left, it subsides immediately if I apply the brakes ( even lightly ) Can only hear it when windows are down
The discs have never been replaced in 23 years but the pads have about 10 months ago ( brembos )

Any ideas ? I am thinking the discs are old and need to be replaced
I will get the car in the air when I get a chance and see if I can see anything off such as uneven pad wear or dry sliders
Tracking needs to be done as I have done a lot of suspension work on the car including control arms/track rod end/struts

Thanks

Could be something as minor as a stone or some other foreign object caught up somewhere ; best thing is to have the wheels off and a good visual inspection , turning the wheels each way to look for anything fouling .

 

[Pontoneer]

Right.
I have checked the propshaft/handbrake cable situation. Behind the transmission sump I can see three blue clips, all holding the handbrake cable in place securely, so that looks fine.
I have replaced pads and discs, noise still there.

Upon inspection, there is a tiny bit of play 12 and 6 when rocking the wheel, but not in any other directions ( I think it is the other control arm that I have not replaced yet causing this )
Not sure if it could be bearing related? It stops " scratching " when applying the brake. And does not sound like a growling noise that a bad bearing usually would.

Any suggestions welcome, thanks.

BTW the tracking will be out by a fair bit due to all the work I've done on it, getting round to that this week ( car drives straight and does not pull )

Brake backing plate touching either the disc or the wheel ( to check for the latter , inspect the inner side of your road wheel for any scratches ) ; for the former , a visual inspection should reveal if the back plate is anywhere close to the disc at any point .

 

[VenomX]

23 years ? how are the backplates/dust shields ?? on my 19 year old C class they are WELL crusty and OEM . ...another job on the list

Just in case you want to go with the handbrake cable theory this is what you are looking for. By the way when my handbrake cable did this the noise sounded like it was coming from the torque converter area forward of the gear selector , very odd noises.

At that age the blue plastic clip could have rotted and let go. As in my photo. Do not discount this theory , it's a pretty easy one to check for yourself.

View attachment 171193

Hi. Yeah I have checked that, thanks. I can see three blue clips holding that handbrake cable in place above the prop ( just behind the ATF sump ). No issue there. As said, when I apply the brake it instantly stops. Which is why I think it is brake related.
Pads/discs/sliders been done. No noise when in the air, only when on the ground driving.

 

[VenomX]

Brake backing plate touching either the disc or the wheel ( to check for the latter , inspect the inner side of your road wheel for any scratches ) ; for the former , a visual inspection should reveal if the back plate is anywhere close to the disc at any point .

I replaced the pads and discs recently. All seemed fine. I will check to see if anything is touching the wheel itself when I get a chance

 

[Pontoneer]

With the car in the air if I spin the wheel, no noise. On the ground, it does make a scratch when driving. The only thing that changes then is how the wheel sits.
Could potentially be if the tracking is out after all the suspension work done on the car, the wheel is not correctly toe in/out , and the pads are therefore rubbing against the disc ?

Toe in/out should not affect relationship of pads to the disc , the discs may just move slightly in relation to the calliper if the wheel bearing is worn , but there would need to be some noticeable play before this would happen . Front wheel bearings are usually not that hard to replace .

 

[VenomX]

Toe in/out should not affect relationship of pads to the disc , the discs may just move slightly in relation to the calliper if the wheel bearing is worn , but there would need to be some noticeable play before this would happen . Front wheel bearings are usually not that hard to replace .

Yeah only reason I say tracking could be causing it is because there is no noise in the air, more noise on the ground, and even more noise when someone sits in the passenger seat. This could be the geometry/position of the wheel changing under load and then scratching the brakes causing the noise.

I will get the alignment done, as it never has been since I owned it and see if the camber is out or anything too.

 

[Pontoneer]

Worth trying , otherwise time to find an expert who knows the cars inside out .

No abnormal tyre wear ?

Sorry , I’m now just guessing .

 

[VenomX]

Worth trying , otherwise time to find an expert who knows the cars inside out .

No abnormal tyre wear ?

Sorry , I’m now just guessing .

No worries any suggestion is welcome.
Checked the tyres with a digital gauge and both front tyres are very similar except for the inside tread. The inside tread on the scratchy wheel is about half a mm higher than the other tyre ( possibly indicating a difference in camber ). Could be nothing, but I will get the tracking done and take it from there.

 

[Pontoneer]

No worries any suggestion is welcome.
Checked the tyres with a digital gauge and both front tyres are very similar except for the inside tread. The inside tread on the scratchy wheel is about half a mm higher than the other tyre ( possibly indicating a difference in camber ). Could be nothing, but I will get the tracking done and take it from there.

Good luck