Scraping or twanging sound.

KenONeill · 08-05-2008, 09:40

TDi110 on 78_000 ish.

Fitted with new rear discs and pads about 2 weeks back.

Now has a noise, sounds like a scrape from inside the car, or more like a twang from outside, seeming to come from the LH rear corner.

Noise is related to road speed, and sometimes goes away when, or as a result of, braking.

I'm thinking that maybe a pad, clip or shim is mis-aligned, or if there's a locating pin for the HB function it's not picking up correctly.

My only other theory for now is that there's damage inside the tyre.

Any other thoughts? (esp from the mechanics)

phillip · 08-05-2008, 10:33

It could be the tin back-plate rubbing on the disc...jack it up, remove the wheel and spin the disc, if you can hear it, then just bend the back plate away from the disc in the relevant area

.

KenONeill · 08-05-2008, 11:03

Nice thought, but we tried that last night (well with the wheel still attached).

We also had a good poke about the underbody, and there's nothing obvious rubbing anywhere, and the exhaust is correctly hung.

cheezemonkhai · 08-05-2008, 11:17

Take the pads out, lube up the sliders and then put it all back together.

Do the pads have the chamfered edges?

Regarding the tyre damage, try the spare?

KenONeill · 08-05-2008, 11:37

Pads were fitted with Copaslip (just visible on edges of backplates.

Probably pattern parts, so I doubt is if the chamfer's an OEM thing.

I honestly think the problem's more likely the brake, cos it sometimes stops completely when or after you brake. That said, if it is the tyre, I'll be talking to Toyo, because the rears don't get big hits compared with the fronts (caused by having to drive over rough patches when hard on brakes).

Bodge · 08-05-2008, 11:51

what about the brake pad retaining springs that are fitted into the brake carrier?

they are more like shims than springs to me, but thats what skoda call them!

suppose one could be damaged/misaligned. they look like they would cause the sound your describing if they were to rub on the disc.

they are quite flimsy.

only way to know for sure is to whip off the calliper i guess...

cheezemonkhai · 08-05-2008, 11:56

If it's a scrape/knocking noise I'd be tempted to get some fine sand paper and just take off the leading edge by a couple of mm on the pad and see if that stops it.

Otherwise I take it the disk is the correct one and isn't contacting the carrier in any way.

KenONeill · 08-05-2008, 12:23

Quote:

Originally Posted by Bodge

what about the brake pad retaining springs that are fitted into the brake carrier?

they are more like shims than springs to me, but thats what skoda call them!

suppose one could be damaged/misaligned. they look like they would cause the sound your describing if they were to rub on the disc.

they are quite flimsy.

only way to know for sure is to whip off the calliper i guess...

That's the sort of way I was thinking, but I was specifically trying to not suggest that as the cause until someone else said it.

KenONeill · 08-05-2008, 12:26

Quote:

Originally Posted by cheezemonkhai

If it's a scrape/knocking noise I'd be tempted to get some fine sand paper and just take off the leading edge by a couple of mm on the pad and see if that stops it.

Otherwise I take it the disk is the correct one and isn't contacting the carrier in any way.

Perhaps I should have said that it happens going backwards as well as forwards then. Also (and a mechanic at the garage who fitted the brakes has already agreed this) it's very definite that the sound comes from one corner and not the other.

KenONeill · 08-05-2008, 15:05

Thanks guys. Panic over; turns out it was a stone trapped under the dust shield!

Taxi 219 · 08-05-2008, 19:03

thats a good cheap result

08-05-2008, 09:40	#1
KenONeill Briskodian Join Date: May 2006 Location: Normally somewhere in Scotland! Posts: 9,457 Thanks: 46 Thanked 437 Times in 430 Posts	Scraping or twanging sound. TDi110 on 78_000 ish. Fitted with new rear discs and pads about 2 weeks back. Now has a noise, sounds like a scrape from inside the car, or more like a twang from outside, seeming to come from the LH rear corner. Noise is related to road speed, and sometimes goes away when, or as a result of, braking. I'm thinking that maybe a pad, clip or shim is mis-aligned, or if there's a locating pin for the HB function it's not picking up correctly. My only other theory for now is that there's damage inside the tyre. Any other thoughts? (esp from the mechanics)

08-05-2008, 10:33	#2
phillip Briskodian Join Date: Jan 2007 Location: west yorks Posts: 165 Thanks: 0 Thanked 5 Times in 3 Posts	Re: Scraping or twanging sound. It could be the tin back-plate rubbing on the disc...jack it up, remove the wheel and spin the disc, if you can hear it, then just bend the back plate away from the disc in the relevant area . __________________ PROTECTING THE PEOPLE OF THIS WORLD FROM THE SCUMBAGS OF THE UNIVERSE !!!

08-05-2008, 11:03	#3
KenONeill Briskodian Join Date: May 2006 Location: Normally somewhere in Scotland! Posts: 9,457 Thanks: 46 Thanked 437 Times in 430 Posts	Re: Scraping or twanging sound. Nice thought, but we tried that last night (well with the wheel still attached). We also had a good poke about the underbody, and there's nothing obvious rubbing anywhere, and the exhaust is correctly hung.

08-05-2008, 11:17	#4
cheezemonkhai Briskodian Join Date: Jan 2006 Posts: 13,778 Thanks: 77 Thanked 341 Times in 315 Posts	Re: Scraping or twanging sound. Take the pads out, lube up the sliders and then put it all back together. Do the pads have the chamfered edges? Regarding the tyre damage, try the spare? __________________ Cars make CO2 and trees absorb CO2. By driving your car you're feeding a tree and helping the environment.

08-05-2008, 11:37	#5
KenONeill Briskodian Join Date: May 2006 Location: Normally somewhere in Scotland! Posts: 9,457 Thanks: 46 Thanked 437 Times in 430 Posts	Re: Scraping or twanging sound. Pads were fitted with Copaslip (just visible on edges of backplates. Probably pattern parts, so I doubt is if the chamfer's an OEM thing. I honestly think the problem's more likely the brake, cos it sometimes stops completely when or after you brake. That said, if it is the tyre, I'll be talking to Toyo, because the rears don't get big hits compared with the fronts (caused by having to drive over rough patches when hard on brakes).

08-05-2008, 11:51	#6
Bodge Briskodian Join Date: Sep 2007 Location: Salisbury or Huddersfield Posts: 510 Thanks: 72 Thanked 43 Times in 40 Posts	Re: Scraping or twanging sound. what about the brake pad retaining springs that are fitted into the brake carrier? they are more like shims than springs to me, but thats what skoda call them! suppose one could be damaged/misaligned. they look like they would cause the sound your describing if they were to rub on the disc. they are quite flimsy. only way to know for sure is to whip off the calliper i guess... __________________ K&N panel, Forge FMCL007P, ECS mag plug, Kumho KU31's up front, Avon ZV3's rear, Philips X-treme Power headlights, Philips SilverVision indicator bulbs, Valeo Silencio X.TRM wiper blades, Ripspeed black 12cm aerial, Mintex Xtreme pads all round, Alpine CDE-9880R, Castrol Edge 5W-30, Always 97-100RON fuel, and alot of TLC!

08-05-2008, 11:56	#7
cheezemonkhai Briskodian Join Date: Jan 2006 Posts: 13,778 Thanks: 77 Thanked 341 Times in 315 Posts	Re: Scraping or twanging sound. If it's a scrape/knocking noise I'd be tempted to get some fine sand paper and just take off the leading edge by a couple of mm on the pad and see if that stops it. Otherwise I take it the disk is the correct one and isn't contacting the carrier in any way. __________________ Cars make CO2 and trees absorb CO2. By driving your car you're feeding a tree and helping the environment.

08-05-2008, 15:05	#10
KenONeill Briskodian Join Date: May 2006 Location: Normally somewhere in Scotland! Posts: 9,457 Thanks: 46 Thanked 437 Times in 430 Posts	Re: Scraping or twanging sound. Thanks guys. Panic over; turns out it was a stone trapped under the dust shield!

08-05-2008, 19:03	#11
Taxi 219 Get out the way Join Date: Oct 2007 Location: Bournemouth Posts: 1,921 Thanks: 64 Thanked 80 Times in 77 Posts	Re: Scraping or twanging sound. thats a good cheap result __________________ Car now: 56 Octavia MK2 1.9TDi Ambiente Previous: 06 Octavia Mk1 1.9TDi Classic with + pack Sadly missed: 97 Nissan Primera 2.0TDi SLX

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