Shuddering when brakes applied between 35-45 mph ('02 A6)

[_sc_]

Hi, I have a 2002 A6 1.9tdi estate and have a strange brake problem. When I apply the brakes between 35 and 45 mph the front shudders. This does not happen at any other speed. Has anyone experienced this previously, and if so I would be grateful if anyone knew how to fix it.

Thanks.
_sc_

[NickPicks]

Is this shuddering like the ABS is modulating? Or shuddering like the disk is warped / contaminated?

If it's that the ABS is modulating, then you can check what's happenning by using the measuring blocks in vag-com.

If it's that the disks are warped (or that there is friction material contaminating the disk), then replace the disks and pads.

I'm suprised it's only hapenning in such a narrow speed band. Does it shudder at all at higher / lower speed?

I suppose it could also be caused by wear in the suspension components.

[_sc_]

Thanks for your suggestions.

The discs and pads have recently been replaced (I've just bought the car so I'm not sure whether this was occurring before the disc/ pad change).

It really only shudders between these speeds. There is a very slight shudder outside this window, but it is very minor and hardly noticeable

[Peter D]

First suspicion is that the new disc making surface was not cleaned property so the disc appear to run out of true and this cuased patch of sheed that when braking modulate the effect. At lower speeds you probabley would not feel it so much and higher speeds will feel more like a vibration. Regards Peter

[Shroud]

Cheap discs are a likely cause IMHO, bought a pair on a previous Forester and had shuddering when dropping speed from c 60 mph, but didn't notice at lower speeds below 40 mph. replaced the discs and shuddering was gone.

[Clinterous]

If you do go down the route of new discs, it is worthwhile making sure the calipers and servo are in good working order first. If they are not tip top the warped disc problem will return.

[NickPicks]

Just another thought: Have you checked the wheels / tyres for balance and roundness? I know that tyre balance usually makes constant vibrations at higher speed (usually about 60), but it might be adding to the effect.

[Peter D]

Yep could be a tyre or bent rim problem. Regards Peter