ABS Fault or Warped Discs

[TehRin]

Hi all,

My car has developed a problem that when I brake I feel a judder through the pedal (almost like an ABS system kicking in), however when braking at higher speeds the judder gets faster. I would have thought that an ABS system would pump the brakes at the same speed if it detected a wheel locking up regardless of whatever speed the vehicle was travelling at, for that reason I think it's possibly a warped disc, does this sound correct?

The judder also becomes more noticeable when braking harder, to the point where it can be felt though the car, however not though the steering wheel or violent either.

The previous owner told me this fault was down the the ABS kicking in because the pads needed to be changed however I can't see how this would cause the ABS to kick in (I could be wrong though), as I'm sure the ABS works off wheel speed sensors (the car is an Audi A4 B6).

[GreenV8S]

Could be uneven deposits on the discs, or very worn pads, or worn sliders, or something loose that shouldn't be. A brake service would address most of these and show whether you had a more serious problem.

[Penelope Stopit]

Could try disconnecting ABS pump and go for a short run

[davidexige]

If you can’t feel it through the steering wheel my first though would be rear discs need changing.