Warranty/brake/defect correction issue

Good morning all of you. Me, more precisely my V70 shakes again a problem. Thicker = V70, 140hp suction cup, EZ: 11.2000, Mj.01 20.February 2009: Car purchased from a Renault dealer, with a one-year car guarantee (so one divided into these 2×6 months ) 21.04.2009 was criticized by a Volvo workshop front brake discs: Unround running, vibration, hitting 08.05.2009 the Renault man changed the windows and coverings Since December I noticed a similar feeling b And since we have spent just under 2.5k kilometers on highway and highway over the turn of the year you get scared to brake again because the entire car is bucking…. Running performance since the change (estimated unfortunately only because I just saw the two workshops had noted wrong km stands): around the 10,000km, maybe 12,000km. Now the question is, is this my problem? Or does the car warranty itself take hold within the year? Or is it a very gentle brake? in rework, because in the first half of the year the dealer has never found the cause removed? No matter what comes out, it annoys a bit of Regards Tom