ABS probs ? Thudding/clunk noise under braking

Hi everyone,

Hope someone can shed some light on this !!

I have a 2003 Octy vRS, and I have recently encountered probs under braking.

Firstly, I noticed that the ABS and Traction Control warning lights would light up together, basically anytime they felt like it ! Then the next time I would get in the car they would be off. Then they would come on again at some point, then off, then on again a bit later, then the ABS light would perhaps light up on its own the next day...you get the picture by now ? Anyway further to this, if I was pulling up to a junction or traffic lights perhaps then under braking I would feel quite a violent thudding/clunking sensation through the brake pedal and also quite a loud clunking noise. This would be quite erratic and only do it now and then, similar to the erratic warning lights. One day the car is fine, the next it throws up all the above symptoms !!

I have had ABS sensor replaced today, but the "clunking" noise/sensation under braking has appeared again !!! Any ideas ?

Cheers,

Lee