Grating scraping noise

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Noonoo632
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Grating scraping noise

Post by Noonoo632 »

So after travelling for a few miles whilst coming to a stop at traffic lights could hear a grating/ scraping noise from under the car which disappeared as I gained speed. On coming to a stop at home noise re-appeared, looking under car nothing obvious /hanging down etc.
Does anyone have any idea what it could be??
Car was serviced 2 weeks ago!!
Stuart_Rendall
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Re: Grating scraping noise

Post by Stuart_Rendall »

Noonoo632 wrote: Wed Mar 31, 2021 6:18 pm So after travelling for a few miles whilst coming to a stop at traffic lights could hear a grating/ scraping noise from under the car which disappeared as I gained speed. On coming to a stop at home noise re-appeared, looking under car nothing obvious /hanging down etc.
Does anyone have any idea what it could be??
Car was serviced 2 weeks ago!!
If it's bad then keep the driving to a minimum and take the car to VW and have them look at the car. Had a similar issue a few years back with an old car. Took it to VW for an M.O.T and a month later had a knocking and grinding sound and turned out to be a badly fastened drive shaft that had eaten its way into the gearbox. Probably won't be the same (hopefully) but best to take it to VW and have them sort it under warranty to be sure.
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Noonoo632
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Re: Grating scraping noise

Post by Noonoo632 »

Stuart_Rendall wrote: Wed Mar 31, 2021 7:15 pm
Noonoo632 wrote: Wed Mar 31, 2021 6:18 pm So after travelling for a few miles whilst coming to a stop at traffic lights could hear a grating/ scraping noise from under the car which disappeared as I gained speed. On coming to a stop at home noise re-appeared, looking under car nothing obvious /hanging down etc.
Does anyone have any idea what it could be??
Car was serviced 2 weeks ago!!
If it's bad then keep the driving to a minimum and take the car to VW and have them look at the car. Had a similar issue a few years back with an old car. Took it to VW for an M.O.T and a month later had a knocking and grinding sound and turned out to be a badly fastened drive shaft that had eaten its way into the gearbox. Probably won't be the same (hopefully) but best to take it to VW and have them sort it under warranty to be sure.
I have got it booked in for Monday and my son is going to have a look at the underside before that to see if there is anything obvious. It was a first service that was done a couple if weeks ago so just an oil and filter change and a complimentary ( i.e. lets see if we can find something charegable) health check.
It is happening when wheels are moving at very low speed!!!
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Re: Grating scraping noise

Post by johnparker »

Do you park on a gravel driveway by any chance? This sounds very similar to my experience which turned out to be a 30mm piece of gravel sat in a cavity in the top of the front wheel bearing housing. The bottom of the cavity is open and close to the top of the rotating hub so the stone was occasionally finding it's way into the 5mm gap between the 2 parts. It must have stuck to the tyre while parked on the drive and then when I pulled away it fell off the top of the tyre and fell behind the wheel into the cavity.
The AA man found it with the car jacked up and wheel removed but I reckon you could feel around for it with the car on the ground and the steering on full lock.
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Noonoo632
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Re: Grating scraping noise

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johnparker wrote: Wed Mar 31, 2021 8:26 pm Do you park on a gravel driveway by any chance? This sounds very similar to my experience which turned out to be a 30mm piece of gravel sat in a cavity in the top of the front wheel bearing housing. The bottom of the cavity is open and close to the top of the rotating hub so the stone was occasionally finding it's way into the 5mm gap between the 2 parts. It must have stuck to the tyre while parked on the drive and then when I pulled away it fell off the top of the tyre and fell behind the wheel into the cavity.
The AA man found it with the car jacked up and wheel removed but I reckon you could feel around for it with the car on the ground and the steering on full lock.
Yes the rear wheels are on chips and tyres do drag them forward and stick to the tyres. I will investigate that possibility when my son comes over, thanks for the heads up
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Re: Grating scraping noise

Post by Andy Beats »

I'm going for stone stuck between a disc and the bloody tin 'guards' that manufacturers insist on fitting.
I honestly can't remember the last car that, at some time, I've not had to bend the tin guard, either to release a trapped stone or just because it's been bashed and is rubbing.
I've become used to routinely bending the tin guards when I change pads anyway, as a preventative measure.
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Noonoo632
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Re: Grating scraping noise

Post by Noonoo632 »

Andy Beats wrote: Thu Apr 01, 2021 9:01 am I'm going for stone stuck between a disc and the bloody tin 'guards' that manufacturers insist on fitting.
I honestly can't remember the last car that, at some time, I've not had to bend the tin guard, either to release a trapped stone or just because it's been bashed and is rubbing.
I've become used to routinely bending the tin guards when I change pads anyway, as a preventative measure.
I am hoping it is that and possibly one of the rear wheels as these are the ones that rest on stone chips. Cannot determine inside the car where noise is coming from hence my son coming up to help locate the noise ( being deaf in one ear does not help🤭 ). Will see later as he is coming up before going to his work.
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Re: Grating scraping noise

Post by Andy Beats »

Noonoo632 wrote: Thu Apr 01, 2021 9:33 am I am hoping it is that and possibly one of the rear wheels as these are the ones that rest on stone chips. Cannot determine inside the car where noise is coming from hence my son coming up to help locate the noise ( being deaf in one ear does not help🤭 ). Will see later as he is coming up before going to his work.
I think your car has discs at the back, I'm sure the 115bhp does whereas the 95bhp has drums (and is better for it, to be honest, discs on the back of normal cars are just hassle).
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Noonoo632
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Re: Grating scraping noise

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Andy Beats wrote: Thu Apr 01, 2021 11:57 am
Noonoo632 wrote: Thu Apr 01, 2021 9:33 am I am hoping it is that and possibly one of the rear wheels as these are the ones that rest on stone chips. Cannot determine inside the car where noise is coming from hence my son coming up to help locate the noise ( being deaf in one ear does not help🤭 ). Will see later as he is coming up before going to his work.
I think your car has discs at the back, I'm sure the 115bhp does whereas the 95bhp has drums (and is better for it, to be honest, discs on the back of normal cars are just hassle).
Yes discs on the back which I also had on my Seat Leon and had no issues but I think the wheels were much further forward and did not go onto the stone chips as far back as Polo rear wheels do!!
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Noonoo632
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Re: Grating scraping noise

Post by Noonoo632 »

Update to "the noise" . So it happens at low speed or when parking while braking either going forward or in reverse on front brakes and can hear what seems like a sloshing sound as well!! This could be petrol in the tank that I am hearing as radio is off??
Next step is to get my son to remove front wheels one at a time and investigate further when he is off at weekend.
You do not hear anything while travelling at normal speed!!
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Re: Grating scraping noise

Post by SRGTD »

Noonoo632 wrote: Thu Apr 01, 2021 3:40 pm Update to "the noise" . So it happens at low speed or when parking while braking either going forward or in reverse on front brakes and can hear what seems like a sloshing sound as well!! This could be petrol in the tank that I am hearing as radio is off??
Next step is to get my son to remove front wheels one at a time and investigate further when he is off at weekend.
You do not hear anything while travelling at normal speed!!
Could it be that the grating / scraping noise is just be the normal action of the abrasive surface of the brake pads making contact with the brake discs while braking at low speed and during parking manoeuvres? Depending on the brake pad material used, some brake pads are noisier than others, and when you’re travelling at slow speeds or performing parking manoeuvres, any braking noise will be more obvious as many of the noises associated with with driving at ‘normal’ speeds (e.g. engine, tyre and wind etc.) either won’t be present or will be much less pronounced.

As for the sloshing sound; I’ve not noticed this with my Polo, although many years ago I owned a Ford which must’ve had poor sound insulation and I could regularly hear the petrol sloshing around in the tank - especially when braking to a stop.
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Noonoo632
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Re: Grating scraping noise

Post by Noonoo632 »

The car has done 3½ k miles and the brakes have been faultless, no noise at all even on reverse but this just started after a 30 mile trip on Wednesday which I cannot understand as you would think that the pads would be well bedded in by now?
Came down a dual carriageway at 70 and as I approached a set of traffic lights got this horrible scraping grating noise which I thought was the car that had drawn up beside me but it is definately my Polo as happened again at next set of lights on single road!!
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Re: Grating scraping noise

Post by Andy Beats »

Are there any obvious grooves in the front discs, or do they look evenly worn across the surface?
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Noonoo632
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Re: Grating scraping noise

Post by Noonoo632 »

Just been out and checked and they are as smooth as a babies proverbial lol
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Noonoo632
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Re: Grating scraping noise

Post by Noonoo632 »

My son has just been over and it's definately nearside front wheel when brakes are applied, attempted to get wheel off but it's seized to the hub as usual so dealers it is on Monday
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