problem with vibration when braking

**noogman** · 22-01-2016,08:01 PM

Hi all.

I have some problem with vibration when braking from high speed. When driving in the city all looks fine. However when driving around 90mph and start braking brake pedal starts vibrating till around 50 mph(steering wheel too but not as much as pedal). Below 50mph there is no vibration or is impossible to feel.

Does any body know what can be a reason of it. Someone said to me that brake discs maybe out of shape or about to end. If yes which one front or rear? Week ago was changing front tyres and when tyres were taken out of axle I was trying to turn the discs around. It was possible however very hard. Today was changing rear tyres and I could have turned rear disc much more easier then front one. Does it mean that front one are out of shape.

Or maybe something completely different. Do you have any idea. Just to mention that camber and alignment is done and is correct?

Thank you for any help

**Guest 2** · 22-01-2016,08:03 PM

how many miles on the car? it sounds like brake judder which would suggest your discs need changing.

**AtotheK** · 22-01-2016,08:05 PM

Sounds like the front discs are coming to end of their life. Obviously they bare the brunt of braking heft so it follows that they may go first.
I had the same symptom on my 2007 A6 which did indeed turn out to be discs...
I hope this helps. A

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**noogman** · 22-01-2016,08:22 PM

Car has 93000 on the clock. Front one are new changed around 30k miles ago and there is no sharp edge on the inner side. But the rears have the sharp edge already and when I look at them I can see brownish colour (hope you know what I mean) and probably are from new. Some one said to me that rear brakes do not work with full power on low speed and start working fully on high speed. I could explain reason why it vibrates on high speed not on low speed. Am I correct?

**AtotheK** · 22-01-2016,08:27 PM

If your fronts are only 30k old and the tears 93k then that suggests rears. I should have asked the obvious questions Chris did instead of jumping to conclusions... My bad!
But in any case the symptom does point to discs.

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**noogman** · 22-01-2016,08:39 PM

Someone also said to me that it could be wishbone. Hope not as more expensive. What do you think?

**AtotheK** · 22-01-2016,08:46 PM

Can't see why a wishbone would only vibrate as you describe it. I would have thought it would be a more constant problem as it is a suspension component that is in use constantly and that it might also show an affect when manouvering/turning etc.
But excuse me, I'm no mechanic/expert in this matter. It's just that what you describe sounds very like what I encountered shortly before my discs went...
Nothing for it but to hit up your local dealer, they'll surely investigate it for you and most likely for free (at least they do if they're Robinsons Audi of Norwich...)

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