Noisy Braking

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tonyb1
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Noisy Braking

Post by tonyb1 »

Hi Guys. I've got a bit of a worry with my brakes. If I'm at speed (50mph+) and start braking to slow down fairly quickly, at a roundabout or lights, the brakes make a loud friction noise, almost like a motor shutting down. It doesn't make any noise at slower speeds. The car stops ok with the noise going. Any ideas? Thanks.
Last edited by tonyb1 on 08 Aug 2006, 21:54, edited 2 times in total.
Xantia 1.9 TD LX 1994 - 152,000 miles and running, strange vibrations
jeremy
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Post by jeremy »

I'm not surprised - my car has BRAKES - not breakes.
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tonyb1
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Post by tonyb1 »

LOL!!!!! Duh! I think I need a break
Xantia 1.9 TD LX 1994 - 152,000 miles and running, strange vibrations
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AndersDK
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Post by AndersDK »

tonyb1 wrote:LOL!!!!! Duh! I think I need a break
- ahhh - not really - I think you ought to at least inspect your brakes - A*S*A*P :roll:

The worst thing you can do as a driver is to ignore loud & clear symptoms from the brakes :?
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2.1td
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Pad check?

Post by 2.1td »

You have checked the pads and discs haven't you? Pads worn down to the metal will give a sound like a train pulling up as they use metal blocks on metal wheel rims, hence all the screeching! :shock: Just thought, you're not mistaking the abs activation are you? That of course makes a very distinctive noise accompanied by a vibrating brake pedal. Mind you, you'd really have to be braking hard to activate abs under normal conditions. Oddly my abs comes in if I brake immediately after passing over certain speed humps! :roll:
Be careful!
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Mandrake
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Re: Pad check?

Post by Mandrake »

2.1td wrote:Oddly my abs comes in if I brake immediately after passing over certain speed humps! :roll:
So does mine!!

There is a large double judder bump at work and when I pass over it (usually braking at the same time) as the back wheels go over the bump I feel the pedal doing ABS pulsing...

I thought I might have an intermitant wire to one of the rear ABS sensors, but it does it pretty consistently, so maybe there is something else going on... like the computer being fooled by the sudden brief change in wheel velocity as the wheel travels over the bump ??

Regards,
Simon
Simon

1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White

2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
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jeremy
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Post by jeremy »

Having listened to my ABS sensors (sad but true - and - no I wasn't bored) I was surprised at how much difference a bump made - which I suppose means that the processor must take this into account when making decisions.

It could be that it will ignore one bump - but thinks the speed change on the second is something it should react to. Could be interesting to try and work out what does trigger it!
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Kowalski
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Post by Kowalski »

When you compress the rear suspension on a Xantia, the length of the wheelbase changes. If the length of the wheelbase changes, the rear wheels will speed up and slow down, is that enough to trigger the ABS?
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2.1td
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Abs tricked?

Post by 2.1td »

Could it also be that as the humps are really a quite abnormal and aggressive bump situation both front wheels rapidly move upwards, then at the top of the hump the sensors detect sudden "lightness" and interpret it as a potential skid situation? And of course to aggravate matters, being Xantia drivers we don't slow down over these humps as much as drivers of cars with more "conventional" suspension systems do... do we?! :lol:
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Mandrake
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Post by Mandrake »

Kowalski wrote:When you compress the rear suspension on a Xantia, the length of the wheelbase changes. If the length of the wheelbase changes, the rear wheels will speed up and slow down, is that enough to trigger the ABS?
The change in wheelbase is very small... its only about 30mm for the entire rear suspension travel, so I doubt that is it...

What I'm getting at is that the rear wheels going over a large curved speed bump are travelling further than the front wheels, and therefore their relative speed must increase compared to the front wheels traveling on a flat piece of ground....

Maybe large but abrupt speed bumps cause enough of a sudden change in relative wheel velocity to confuse the computer...

Regards,
Simon
Simon

1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White

2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
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